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University of Arizona
1.
Cena, Jacob Anthony.
Evaluation of Cross-talk in Electromyographic Signals
.
Degree: 2014, University of Arizona
URL: http://hdl.handle.net/10150/347116
► Activity of skeletal muscles produce electrical signals that can be measured using electrodes placed on the skin surface over a target muscle or with electrodes…
(more)
▼ Activity of skeletal muscles produce electrical signals that can be measured using electrodes placed on the skin surface over a target muscle or with electrodes inserted into the muscle. Such electromyographic (EMG) signals provide fundamental information about the intensity of the neural drive acting upon muscle. In addition, EMG signals are widely deployed as control sources for powered prosthetic limbs. One limitation related to recording EMG signals, however, is that signals arising from neighboring muscles may contribute significantly to the activity detected with electrodes placed over or within a given target muscle. Such unwanted contribution of signal from muscles other than the targeted muscle is referred to as cross-talk. Cross-talk was investigated in four neighboring muscles in the forearm with different electrode types and configurations: bipolar intramuscular, monopolar intramuscular, and bipolar surface EMG. Cross-correlation analysis was performed for every pairwise combination of EMG signal recorded. The peak correlation coefficient at near-zero time delay provided an index of the degree of cross-talk. Correlation coefficients dropped off exponentially with distance between recording electrodes. Bipolar intramuscular EMG had the narrowest pick-up range, with a length constant of 14.5 mm. Bipolar surface EMG had a longer length constant of 37.0 mm, whereas monopolar intramuscular EMG had the longest length constant of 64.5 mm. A second set of experiments indicated that correlation in EMG signals detected in different muscles was unlikely to have a neural basis. Therefore, because of their wide detection range, monopolar configurations including those involving intramuscular electrodes, should be avoided.
Advisors/Committee Members: Fuglevand, Andrew J (advisor), Fuglevand, Andrew J. (committeemember), Eggers, Erika (committeemember), Fregosi, Ralph (committeemember).
Subjects/Keywords: cross-talk;
EMG;
intramuscular;
monopolar;
surface;
Biomedical Engineering;
bipolar
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APA (6th Edition):
Cena, J. A. (2014). Evaluation of Cross-talk in Electromyographic Signals
. (Masters Thesis). University of Arizona. Retrieved from http://hdl.handle.net/10150/347116
Chicago Manual of Style (16th Edition):
Cena, Jacob Anthony. “Evaluation of Cross-talk in Electromyographic Signals
.” 2014. Masters Thesis, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/347116.
MLA Handbook (7th Edition):
Cena, Jacob Anthony. “Evaluation of Cross-talk in Electromyographic Signals
.” 2014. Web. 22 Jan 2021.
Vancouver:
Cena JA. Evaluation of Cross-talk in Electromyographic Signals
. [Internet] [Masters thesis]. University of Arizona; 2014. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/347116.
Council of Science Editors:
Cena JA. Evaluation of Cross-talk in Electromyographic Signals
. [Masters Thesis]. University of Arizona; 2014. Available from: http://hdl.handle.net/10150/347116

University of Arizona
2.
Revill, Ann.
Role of Synaptic and Non-Synaptic Mechanisms Underlying Motor Neuron Control
.
Degree: 2011, University of Arizona
URL: http://hdl.handle.net/10150/202994
► While motor neuron activity has been studied for many decades, the relative contribution of synaptic and non-synaptic mechanisms underlying this activity during natural behaviors is…
(more)
▼ While motor neuron activity has been studied for many decades, the relative contribution of synaptic and non-synaptic mechanisms underlying this activity during natural behaviors is not well understood. Thus, the goal of this dissertation was to further understand the role of non-synaptic properties of motor neurons during voluntary activity. In particular, I considered three non-synaptic properties: persistent inward currents (PICs) that boost synaptic inputs, spike-threshold accommodation that affects recruitment threshold as excitation rates of rise slow, and spike-frequency adaptation that leads to a decrease in firing rate despite constant excitation levels. Computer simulations were employed to understand the potential effect that these properties could have on firing rate behavior. In particular, the focus was on paired motor unit recordings where a lower threshold motor unit’s firing rate served as a proxy for synaptic drive, and differences in firing rate (ΔF) were compared at a higher threshold unit’s recruitment and derecruitment. While ΔF has been used by others to estimate PIC activation, the simulation results indicated that each of these non-synaptic mechanisms could lead to positive ΔF. Furthermore, by varying contraction speed and duration it seemed possible to determine which property contributes to ΔF in vivo. The results from human experiments indicated that adaptation is most likely the predominant
contributor to ΔF during natural behaviors. Additionally, positive ΔF was even observed in the genioglossus muscle of the tongue, where the role of PICs has been debated. These results suggested that ΔF may not the best method to detect PICs during natural behaviors. As such, I also considered whether there might be another metric to infer PIC activation during natural behaviors. Motor unit firing rates tend to plateau, or saturate, despite continued force increase, and one hypothesis is that PICs contribute to this behavior. Indeed, motor unit firing rate saturation was diminished by the addition of inhibition, which should have limited PIC activation. Therefore, this final study provided possible evidence for PIC activation during natural behaviors. Overall, this dissertation highlights that non-synaptic properties of motor neurons are activated during natural behaviors and that they contribute significantly to firing rate output.
Advisors/Committee Members: Fuglevand, Andrew J (advisor), Bailey, E. Fiona (committeemember), Fellous, Jean-Marc (committeemember), Fregosi, Ralph (committeemember), Levine, Richard (committeemember), Fuglevand, Andrew J. (committeemember).
Subjects/Keywords: Motor unit;
persistent inward current;
spike-frequency adaptation;
spike-threshold accommodation;
Physiological Sciences;
Motor control;
Motor neuron
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APA ·
Chicago ·
MLA ·
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APA (6th Edition):
Revill, A. (2011). Role of Synaptic and Non-Synaptic Mechanisms Underlying Motor Neuron Control
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/202994
Chicago Manual of Style (16th Edition):
Revill, Ann. “Role of Synaptic and Non-Synaptic Mechanisms Underlying Motor Neuron Control
.” 2011. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/202994.
MLA Handbook (7th Edition):
Revill, Ann. “Role of Synaptic and Non-Synaptic Mechanisms Underlying Motor Neuron Control
.” 2011. Web. 22 Jan 2021.
Vancouver:
Revill A. Role of Synaptic and Non-Synaptic Mechanisms Underlying Motor Neuron Control
. [Internet] [Doctoral dissertation]. University of Arizona; 2011. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/202994.
Council of Science Editors:
Revill A. Role of Synaptic and Non-Synaptic Mechanisms Underlying Motor Neuron Control
. [Doctoral Dissertation]. University of Arizona; 2011. Available from: http://hdl.handle.net/10150/202994

University of Arizona
3.
Masri, Samer.
Roles of Parvalbumin-Expressing Interneurons in Physiological Changes to Primary Auditory Cortex After Hearing Loss and Blast Exposure
.
Degree: 2020, University of Arizona
URL: http://hdl.handle.net/10150/642110
► Hearing loss affects approximately 1 in 8 Americans and has a significant impact on quality of life, often leading to tinnitus and central auditory processing…
(more)
▼ Hearing loss affects approximately 1 in 8 Americans and has a significant impact on quality of life, often leading to tinnitus and central auditory processing disorder. Hearing loss causes a cascade of changes to the auditory processing pathway, starting with death of hair cells in the inner ear and ultimately causing a series of physiological changes in primary auditory cortex (AI). Blast exposure commonly affects veterans and can lead to hearing loss as well as Traumatic Brain Injury (TBI), which damages the soft tissue and vasculature of the central nervous system and can independently cause central auditory processing disorder. The distinct effects of hearing loss and TBI on auditory processing remain poorly understood. Further research is needed to identify the role of AI in auditory processing deficits after hearing loss and/or TBI, as well as to identify specific cellular mechanisms to serve as targets for potential therapeutic approaches.
First, I identify changes to the primary auditory cortex of rats following blast exposure with associated hearing loss. This includes distortions in the normal tonotopic frequency map in the form of random, frequency specific expansions. Additionally, there are associated changes to the hearing threshold and bandwidth of frequency tuning at individual cortical recording sites. These changes outline broad physiological deficits in auditory processing in primary auditory cortex after blast exposure.
Next, I show that blast exposure alone can impair temporal processing in AI, but concurrent hearing loss dramatically exacerbates these impairments. I dissociate the effects of blast exposure and hearing loss by protecting either one or both ears from hearing loss during blast exposure. While blast exposure without hearing loss causes deficits in temporal processing which could lead to central auditory processing disorder, blast exposure with associated hearing loss causes more numerous and severe deficits. Specifically, only blast exposure with concurrent hearing loss reduces the expression of the Parvalbumin protein in AI and causes deficits in gap detection behavior, which is used as a test for potential tinnitus.
Finally, I show that hearing loss alone causes a set of changes to Parvalbumin-expressing inhibitory interneurons (PV neurons) in AI. This includes a reduction of Parvalbumin expression in AI, changes to the gene expression profiles of PV neurons, and an overall reduction in the inhibitory output of PV neurons. These changes are not mirrored in another population of neurons called Somatostatin-expressing interneurons. I show that deficits in gap detection behavior following hearing loss can be rescued by Chemogenetic activation of PV neurons in AI.
Advisors/Committee Members: Bao, Shaowen (advisor), Fuglevand, Andrew (advisor), Nighorn, Alan (committeemember), Cowen, Stephen (committeemember).
Subjects/Keywords: Auditory;
Blast;
Cortex;
Hearing loss;
Interneuron;
Parvalbumin
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Masri, S. (2020). Roles of Parvalbumin-Expressing Interneurons in Physiological Changes to Primary Auditory Cortex After Hearing Loss and Blast Exposure
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/642110
Chicago Manual of Style (16th Edition):
Masri, Samer. “Roles of Parvalbumin-Expressing Interneurons in Physiological Changes to Primary Auditory Cortex After Hearing Loss and Blast Exposure
.” 2020. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/642110.
MLA Handbook (7th Edition):
Masri, Samer. “Roles of Parvalbumin-Expressing Interneurons in Physiological Changes to Primary Auditory Cortex After Hearing Loss and Blast Exposure
.” 2020. Web. 22 Jan 2021.
Vancouver:
Masri S. Roles of Parvalbumin-Expressing Interneurons in Physiological Changes to Primary Auditory Cortex After Hearing Loss and Blast Exposure
. [Internet] [Doctoral dissertation]. University of Arizona; 2020. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/642110.
Council of Science Editors:
Masri S. Roles of Parvalbumin-Expressing Interneurons in Physiological Changes to Primary Auditory Cortex After Hearing Loss and Blast Exposure
. [Doctoral Dissertation]. University of Arizona; 2020. Available from: http://hdl.handle.net/10150/642110

University of Arizona
4.
So, Lisa Yong.
Social Context Differences in Activation of Synaptic Plasticity Pathways in Birdsong
.
Degree: 2020, University of Arizona
URL: http://hdl.handle.net/10150/642193
► Vocal communication is critical for survival and is used by humans and animals for many reasons including socialization, and the inability to communicate is detrimental…
(more)
▼ Vocal communication is critical for survival and is used by humans and animals for many reasons including socialization, and the inability to communicate is detrimental to one’s life. The neural mechanisms underlying vocal communication are poorly understood leading to poor therapeutic options when a dysfunction arises. In humans, Kuhl hypothesized that social interactions enhance the ability to learn speech and language (Kuhl, 2007). The circuitry that encodes for social behavior may gate the acquisition of speech making it important to understand social behaviors and the underlying mechanisms. Songbirds have been used as a model system to gain insight into the central brain mechanisms of vocal communication, particularly the study of behavior in different social contexts.
In chapter two, I focused on the role of dopamine (DA) in social context-dependent differences in song. DA is an important neuromodulator of motor control across species. In zebra finches, DA levels vary in song nucleus Area X depending upon social context. DA levels are high and song output is less variable when a male finch sings to a female (female directed, FD) compared to when he is singing by himself (undirected, UD). DA modulates glutamatergic input onto cortico-striatal synapses in Area X via N-methyl-D-aspartate (NMDA) and DA receptor mechanisms, but the relationship to UD vs. FD song output is unclear. I investigated the expression of molecular markers of dopaminergic and glutamatergic synaptic transmission (tyrosine hydroxylase – TH, alpha-synuclein – α-syn) and plasticity (NMDAR2B – GRIN2B) following singing (UD vs. FD) and non-singing states to understand the molecular mechanisms driving differences in song output. With higher UD song amount, there were increases in TH, α-syn, and NMDAR2B protein levels. By contrast, the amount of FD song did not have a relationship with TH and NMDAR2B expression. Levels of α-syn showed differential expression patterns based on UD vs. FD song, consistent with its role in modulating synaptic transmission. I proposed a molecular pathway model to explain how social context and amount of song are important factors for molecular changes required for synaptic transmission and plasticity.
In chapter three, I honed in on synaptic plasticity molecular pathways as mediators of social context differences in song output. Based on chapter two results, NMDARs were strong targets suggesting the role of synaptic plasticity in social context differences. In addition, a secondary synaptic plasticity pathway involving brain-derived neurotrophic factor (BDNF) and tropomyosin receptor kinase B (TrkB) was chosen since a rise in BDNF levels in a cortical song nucleus increased song learning. Therefore, I identified four molecules downstream of NMDAR and TrkB activation and determined their expression in Area X after UD and FD song: calcium/calmodulin dependent protein kinase II beta (CaMKIIB), homer scaffold protein 1 (HOMER1), serine/threonine protein kinase (Akt), and mechanistic target of rapamycin kinase (mTOR). My…
Advisors/Committee Members: Miller, Julie E (advisor), Fuglevand, Andrew (committeemember), Rance, Naomi (committeemember), Falk, Torsten (committeemember).
Subjects/Keywords: Basal ganglia;
Social context;
Synaptic plasticity;
Zebra finch
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
So, L. Y. (2020). Social Context Differences in Activation of Synaptic Plasticity Pathways in Birdsong
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/642193
Chicago Manual of Style (16th Edition):
So, Lisa Yong. “Social Context Differences in Activation of Synaptic Plasticity Pathways in Birdsong
.” 2020. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/642193.
MLA Handbook (7th Edition):
So, Lisa Yong. “Social Context Differences in Activation of Synaptic Plasticity Pathways in Birdsong
.” 2020. Web. 22 Jan 2021.
Vancouver:
So LY. Social Context Differences in Activation of Synaptic Plasticity Pathways in Birdsong
. [Internet] [Doctoral dissertation]. University of Arizona; 2020. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/642193.
Council of Science Editors:
So LY. Social Context Differences in Activation of Synaptic Plasticity Pathways in Birdsong
. [Doctoral Dissertation]. University of Arizona; 2020. Available from: http://hdl.handle.net/10150/642193

University of Arizona
5.
Wiegand, Jean-Paul.
The Influence of Aging and Parkinson’s Disease on Neural Oscillations Associated with Memory Consolidation
.
Degree: 2018, University of Arizona
URL: http://hdl.handle.net/10150/630167
► Current understanding within the field of neuroscience regarding why the brain requires significant periods of sleep rests upon the existence of extremely stereotypical patterns of…
(more)
▼ Current understanding within the field of neuroscience regarding why the brain requires significant periods of sleep rests upon the existence of extremely
stereotypical patterns of oscillatory neural activity found in almost all mammals.
Within these characteristic patterns of wide-scale neural activity occurs crossregional
synchronization of oscillations of various frequencies and this coupling is
fundamental to the process of memory consolidation. Specifically, high-frequency
oscillations, or ripples, in the hippocampal formation are required for the
conversion of short-term to long-term memory. These ripples couple to two
slower oscillations found in the cortex, delta waves and spindles. The author
describes here his contributions to the field of memory consolidation showing that
hippocampal ripples in aged rats are of decreased frequency during sleep but not
during wake. In addition, it is well documented that with age, behavioral and
neural sleep parameters decrease while the incidence of neurodegenerative
diseases increases. The author will discuss unpublished findings of behavioral
sleep disturbances and changes in cortical sleep oscillations preceding motor
impairment in a LRRK2 mouse model of Parkinson’s disease (PD), and explore
herein putative links between age-related changes in neural oscillations and the
predilection towards neurodegeneration.
Advisors/Committee Members: Cowen, Stephen L (advisor), Fernandez, Fabian (committeemember), Fuglevand, Andrew (committeemember), Falk, Torsten (committeemember).
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Wiegand, J. (2018). The Influence of Aging and Parkinson’s Disease on Neural Oscillations Associated with Memory Consolidation
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/630167
Chicago Manual of Style (16th Edition):
Wiegand, Jean-Paul. “The Influence of Aging and Parkinson’s Disease on Neural Oscillations Associated with Memory Consolidation
.” 2018. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/630167.
MLA Handbook (7th Edition):
Wiegand, Jean-Paul. “The Influence of Aging and Parkinson’s Disease on Neural Oscillations Associated with Memory Consolidation
.” 2018. Web. 22 Jan 2021.
Vancouver:
Wiegand J. The Influence of Aging and Parkinson’s Disease on Neural Oscillations Associated with Memory Consolidation
. [Internet] [Doctoral dissertation]. University of Arizona; 2018. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/630167.
Council of Science Editors:
Wiegand J. The Influence of Aging and Parkinson’s Disease on Neural Oscillations Associated with Memory Consolidation
. [Doctoral Dissertation]. University of Arizona; 2018. Available from: http://hdl.handle.net/10150/630167

University of Arizona
6.
Hill, Daniel.
Examining the Role of Top-Down Signaling and Tegmental Activity in Nucleus Accumbens Dopamine Release
.
Degree: 2019, University of Arizona
URL: http://hdl.handle.net/10150/631888
► The capacity to assess the value of future outcomes based on current context is critical for learning, adaptive decision making, and motivation. In the brain…
(more)
▼ The capacity to assess the value of future outcomes based on current context is critical for learning, adaptive decision making, and motivation. In the brain this requires the integration of many complex signals from multiple brain regions into a unitary value signal. Midbrain dopamine neurons are among the most notable neural substrates associated with outcome valuation and have been shown to be essential for economic decision making, motivation, and error-driven learning. The mechanisms by which complex behavioral and environmental stimuli are distilled down to value signals by dopamine neurons and their afferents remain incompletely understood. This work seeks to better understand the patterns of top-down input and local control that give rise to phasic dopamine release.
To examine how cortical input influences phasic dopamine release, we used fast-scan cyclic voltammetry (FSCV) to measure dopamine release evoked by varying frequencies of electrical stimulation in the medial prefrontal cortex. We found that there is a non-linear response to frequency such that 20 Hz stimulation optimizes dopamine release in the nucleus accumbens (NAc) even when controlling for stimulus duration. These data suggest that specific frequencies of cortical activation preferentially activate dopamine neurons and may have implications for cortical control of dopamine release in circumstances when value encoding must be optimized (e.g., during cognitively demanding tasks involving working memory and attention).
Though electrical and optogenetic stimulation are valuable tools for dissecting functional circuits, they modulate activity in ways that are not physiological and therefore, they cannot be used to assess how endogenous patterns of neural activity influence dopamine release. To address this, we developed a novel instrument capable of simultaneous measurement of dopamine release (FSCV) and neural activity (electrophysiology). This system was validated in vitro and in vivo to show reliable recovery of single-unit activity and local field oscillations while recording changes in phasic dopamine. The real-time correlation of these signals enables the investigation of patterns of activity that drive dopamine release and how dopamine entrains cell assemblies in downstream structures.
Though the relationship between dopamine neuron activity and dopamine release is seemingly intuitive, technological limitations have limited the capacity to measure these signals simultaneously. To better understand how tegmental activity gives rise to changes in dopamine release, we implemented the instrument described above to record FSCV in the nucleus accumbens and single-unit activity in the VTA. As expected, we observed changes in firing rate of putative dopaminergic neurons associated with the onset of phasic dopamine release events. We also observed a number of non-dopaminergic neurons with reliable peri-event changes in firing. Although we expected the majority of non-dopaminergic cells to decrease their activity preceding dopamine release events,…
Advisors/Committee Members: Cowen, Stephen L (advisor), Heien, Michael L. (committeemember), Fuglevand, Andrew (committeemember), Navratilova, Edita (committeemember).
Subjects/Keywords: dopamine;
electrophysiology;
Fast-scan cyclic voltammetry;
medial Prefrontal Cortex (mPFC);
nucleus accumbens (NAc);
ventral tegmental area (VTA)
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Hill, D. (2019). Examining the Role of Top-Down Signaling and Tegmental Activity in Nucleus Accumbens Dopamine Release
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/631888
Chicago Manual of Style (16th Edition):
Hill, Daniel. “Examining the Role of Top-Down Signaling and Tegmental Activity in Nucleus Accumbens Dopamine Release
.” 2019. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/631888.
MLA Handbook (7th Edition):
Hill, Daniel. “Examining the Role of Top-Down Signaling and Tegmental Activity in Nucleus Accumbens Dopamine Release
.” 2019. Web. 22 Jan 2021.
Vancouver:
Hill D. Examining the Role of Top-Down Signaling and Tegmental Activity in Nucleus Accumbens Dopamine Release
. [Internet] [Doctoral dissertation]. University of Arizona; 2019. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/631888.
Council of Science Editors:
Hill D. Examining the Role of Top-Down Signaling and Tegmental Activity in Nucleus Accumbens Dopamine Release
. [Doctoral Dissertation]. University of Arizona; 2019. Available from: http://hdl.handle.net/10150/631888
7.
Buckmire, Alie Johnathon.
Development of an Upper Limb Neuroprosthesis: Conquering Weakness and Fatigue
.
Degree: 2019, University of Arizona
URL: http://hdl.handle.net/10150/633129
► Neuroprosthetics are devices that substitute for or supplant motor, sensory or cognitive modalities damaged as a result of spinal cord injury or stroke. Functional electrical…
(more)
▼ Neuroprosthetics are devices that substitute for or supplant motor, sensory or cognitive modalities damaged as a result of spinal cord injury or stroke. Functional electrical stimulation (FES) neuroprosthetics utilize artificial stimulation to restore motor function in paralyzed muscles, where control exerted by higher nervous system centers over muscle may be impaired. Although promising, FES has failed to gain widespread acceptance due in part to weak contraction strength and rapid fatigue observed with artificial stimulation. This dissertation documents an attempt to create an upper limb FES neuroprosthetic and subsequently to address the issues of weakness and fatigue. To exploit the capabilities of the musculoskeletal system the neural drive to muscle first must be decoded. Decoding the neural drive for specific movements has been approached using either a deterministic (engineering) or machine learning model. While a deterministic model accounts for all components of a limb, number of joints, degrees of freedom, limb length, muscle length, etc, machine learning characterizes the relationship between select variables, in this case whole muscle electromyographic data (EMG) and limb kinematics. Ultimately, the output of both approaches is used to predict the neural drive required to generate movements. In this study we first attempt to build an upper limb FES neuroprosthetic. Utilizing machine learning, we characterize the relationship between limb kinematics and EMG. Then, predict EMG based solely on limb kinematics. Finally, stimulation pulses were generated and delivered via intramuscular electrodes to produce movement. Additionally, to address force generation we hypothesized that due to the distributed nature of motor axons within a muscle stimulating with multiple spatially distributed electrodes would activate a larger muscle volume thus generating additional force. This in turn would facilitate load sharing among muscle fibers, and reduce fatigue. To evaluate fatigue we compared interleaved and synchronous patterns of stimulation as well as single electrode vs multiple electrode stimulation. We approached these questions and aims with a combination of strategies and techniques including machine learning, implantation of stimulating electrodes in a non-human primate model and finally human subjects. While machine learning provided EMG predictions with high R values, we were unable to generate substantive movements activating all the muscle in a complete joint system. However, we were able to generate movements stimulating a single muscle in an intact joint system. We found that single electrode force could be augmented with multiple electrodes. Additional results indicate that multiple electrode stimulation was less fatiguing than single electrode stimulation. Interleaved stimulation however, did not result in less fatigue than synchronous stimulation.
Advisors/Committee Members: Fuglevand, Andrew (advisor), Bailey, Fiona E. (committeemember), Eggers, Erika (committeemember), Fregosi, Ralph (committeemember).
Subjects/Keywords: Functional Electrical Stimulation
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Buckmire, A. J. (2019). Development of an Upper Limb Neuroprosthesis: Conquering Weakness and Fatigue
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/633129
Chicago Manual of Style (16th Edition):
Buckmire, Alie Johnathon. “Development of an Upper Limb Neuroprosthesis: Conquering Weakness and Fatigue
.” 2019. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/633129.
MLA Handbook (7th Edition):
Buckmire, Alie Johnathon. “Development of an Upper Limb Neuroprosthesis: Conquering Weakness and Fatigue
.” 2019. Web. 22 Jan 2021.
Vancouver:
Buckmire AJ. Development of an Upper Limb Neuroprosthesis: Conquering Weakness and Fatigue
. [Internet] [Doctoral dissertation]. University of Arizona; 2019. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/633129.
Council of Science Editors:
Buckmire AJ. Development of an Upper Limb Neuroprosthesis: Conquering Weakness and Fatigue
. [Doctoral Dissertation]. University of Arizona; 2019. Available from: http://hdl.handle.net/10150/633129

University of Arizona
8.
Wong, Bryan M.
Planum Temporale: Morphologic Taxonomy of the Superior Temporal Plane
.
Degree: 2019, University of Arizona
URL: http://hdl.handle.net/10150/636683
► Background: Planum Temporale (PT) is a crucial neuroauditory structure located in the dorsal superior temporal plane (STP) posterior to Heschl’s gyrus (HG). The PT has…
(more)
▼ Background: Planum Temporale (PT) is a crucial neuroauditory structure located in the dorsal superior temporal plane (STP) posterior to Heschl’s gyrus (HG). The PT has been implicated in complex auditory function and is well known for its preponderance of leftward asymmetry in normal brains and classic “pie- shaped” morphology. While a majority of cases have easily identifiable PT and HG, there exist some cases in which distinguishability of these two structures is difficult due to morphological variation. The goal of this study is to create a taxonomy of PT morphological features in order to improve the sometimes difficult identification and differentiation of PT from surrounding structures. Methods: A total of 50 (100 hemispheres) healthy intact, high-resolution T1- weighted brain MRIs were obtained from Open Access Series of Imaging Studies (OASIS) and included in this retrospective study. There were 28 women and 22 men, all right-handed. Ages ranged from 18-57 (mean=26.44) years. A 3D cortical surface mesh (grey matter) for each brain was generated using FreeSurfer and manipulated to view the STP using BrainVISA Anatomist neuroimaging software. The PT was isolated from surrounding structures based on pre-defined anatomical criteria and subsequent surface area measurements, linear measurements and qualitative measures were made. Results: A total of four PT configurations were identified: (1) Pie-shaped [45%], (2) Trapezoid-shaped [27%], (3) Rectangular-shaped [19%], and (4) None [9%]. Mean surface areas of measurable PT configurations were: 511.96 mm2 for “Pie-shaped” (n=45), 517.36 mm2 for “Trapezoid-shaped” (n=27) and 472.12mm2 for “Rectangular-shaped” (n=19). The fourth category, “None” (n=9), was not calculable. There were significantly more “Trapezoid-shaped” PTs in females (p<.05). The “None” category occurred significantly more in males (p<.05) and in the right hemisphere (p<.05). Furthermore, the left hemisphere demonstrated significantly greater surface area for “Pie-shaped” PTs (p<.05). Conclusion: We believe that the proposed classifications is the first step in creating a comprehensive taxonomy of the STP. This will aid neuroanatomists, clinicians and students in terms of differentiation of sometimes complex topography of the STP.
Advisors/Committee Members: Musiek, Frank (advisor), Fuglevand, Andrew (committeemember), Cone, Barbara (committeemember), Kielar, Aneta (committeemember).
Subjects/Keywords: auditory cortex;
heschls gyrus;
planum temporale;
superior temporal plane;
taxonomy
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Wong, B. M. (2019). Planum Temporale: Morphologic Taxonomy of the Superior Temporal Plane
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/636683
Chicago Manual of Style (16th Edition):
Wong, Bryan M. “Planum Temporale: Morphologic Taxonomy of the Superior Temporal Plane
.” 2019. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/636683.
MLA Handbook (7th Edition):
Wong, Bryan M. “Planum Temporale: Morphologic Taxonomy of the Superior Temporal Plane
.” 2019. Web. 22 Jan 2021.
Vancouver:
Wong BM. Planum Temporale: Morphologic Taxonomy of the Superior Temporal Plane
. [Internet] [Doctoral dissertation]. University of Arizona; 2019. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/636683.
Council of Science Editors:
Wong BM. Planum Temporale: Morphologic Taxonomy of the Superior Temporal Plane
. [Doctoral Dissertation]. University of Arizona; 2019. Available from: http://hdl.handle.net/10150/636683

University of Arizona
9.
Arakeri, Tapas Jaywant.
Object Discrimination Using Electrotactile Feedback
.
Degree: 2017, University of Arizona
URL: http://hdl.handle.net/10150/625688
► A variety of bioengineering systems are being developed to restore the sense of touch in individuals who have lost this mode of sensory feedback because…
(more)
▼ A variety of bioengineering systems are being developed to restore the sense of touch in individuals who have lost this mode of sensory feedback because of spinal cord injury, stroke, or amputation. Typically, these systems detect touch pressure on the fingers of an insensate hand (or from a prosthetic hand in the case of amputees) and deliver the detected pressure information to sensate skin above the site of injury (for example, on the back of the neck) by electrically stimulating that skin with an intensity that matches the detected pressure. We implemented a project that involves developing a method to artificially represent tactile and proprioceptive sensations using electrotactile feedback in prosthetic users. Our system uses one set of electrodes to provide information about contact forces applied by the digits and a separate set to indicate aperture of the hand. We tested the ability of five intact human subjects to distinguish objects of varying weight, width and compliance based on electrotactile feedback arising from sensors placed on the hand of an experimenter (not visible to the subject) grasping and lifting the test objects. Over the course of five separate training sessions, we observed a statistically significant (P=0.026) improvement in the mean performance of all subjects. Thus, this study serves as proof that human subjects can learn to make sense of multichannel-multivariable electrotactile feedback to comprehend certain physical features associated with an object.
Advisors/Committee Members: Fuglevand, Andrew J (advisor), Bailey, Elizabeth Fiona (advisor), Fuglevand, Andrew J. (committeemember), Bailey, Elizabeth Fiona (committeemember), Fregosi, Ralph F. (committeemember), Eggers, Erika D. (committeemember).
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Arakeri, T. J. (2017). Object Discrimination Using Electrotactile Feedback
. (Masters Thesis). University of Arizona. Retrieved from http://hdl.handle.net/10150/625688
Chicago Manual of Style (16th Edition):
Arakeri, Tapas Jaywant. “Object Discrimination Using Electrotactile Feedback
.” 2017. Masters Thesis, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/625688.
MLA Handbook (7th Edition):
Arakeri, Tapas Jaywant. “Object Discrimination Using Electrotactile Feedback
.” 2017. Web. 22 Jan 2021.
Vancouver:
Arakeri TJ. Object Discrimination Using Electrotactile Feedback
. [Internet] [Masters thesis]. University of Arizona; 2017. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/625688.
Council of Science Editors:
Arakeri TJ. Object Discrimination Using Electrotactile Feedback
. [Masters Thesis]. University of Arizona; 2017. Available from: http://hdl.handle.net/10150/625688

University of Arizona
10.
Brown, Cecilia.
Genetic Requirements for Building a Brain of Sufficient Size: Insights from Mendelian Congenital Microcephaly Disorders
.
Degree: 2017, University of Arizona
URL: http://hdl.handle.net/10150/625705
► Congenital microcephaly (conMiC) is a manifestation of severely disrupted prenatal brain development, caused by genetic defects, toxins, severe maternal malnutrition, or infection. The Zika virus…
(more)
▼ Congenital microcephaly (conMiC) is a manifestation of severely disrupted prenatal brain development, caused by genetic defects, toxins, severe maternal malnutrition, or infection. The Zika virus outbreak and the devastating impact of Zika infection on the fetal brain have focused much attention on the cellular and molecular pathophysiology of conMiC. Mendelian conMiC disorders offer a unique opportunity for understanding gene and protein networks that direct cellular processes essential for prenatal brain development. Using OMIM and literature searches, I analyzed 68 conMiC disorders and their 65 corresponding genes. ConMiC-disorder phenotypes were characterized by analyzing the co-occurrence of ID, retinal abnormalities, seizures, and short stature. Short stature co-occurred with 70% of conMiC disorders, while seizures and retinopathy co-occurred with 68% and 37%, respectively. In 53% of conMiC disorders, seizures and short stature overlapped, while all features overlapped in 22% of conMiC disorders; only 7% of conMiC disorders lacked one of these co-occurring features. This shows conMiC genes are rarely specialized for brain growth, with generalized functions in overall body growth, retinal development, and/or regulation of neural activity. ConMiC-gene transcript accumulation in the brain is typically greatest during the prenatal period, and then declines postnatally, suggesting active transcriptional repression. Nonetheless, in neurons and glia of the adult brain, 44 conMiC genes had confirmed persistent protein accumulation. Experimental evidence indicates transcription in neural progenitor cells (NPCs) for at least 82% of conMiC genes. The spatiotemporal expression patterns of conMiC genes tend to align well with their biological functions and corresponding mutant phenotypes. Nearly 60% of conMiC gene products have functions in the cell cycle and/or DNA repair. Most conMiC disorders are caused by recessive, loss-of-function mutations. There are direct binding and regulatory interactions amongst many conMiC genes, which interact in larger networks and shared pathways. Depletion of single conMiC gene products can affect the transcript and/or protein levels of other conMiC gene products, which could have a “domino effect”, and disrupt entire networks important for brain development. Further evidence for this model is that 22 conMiC genes are consistently dysregulated in Zika-infected developing human brain tissue. Due to the complexity of conMiC genes and their interactions, there are many unique challenges to developing treatments for conMiC, particularly conMiC caused by maternal Zika-virus infection. However, insights to treatment strategies could be gained by using human genetics to find potential modifiers, screening for drugs that can normalize disrupted cell cycle and DNA-repair processes, or can stabilize protein complexes that are disrupted due to a conMiC gene mutation.
Advisors/Committee Members: Restifo, Linda L (advisor), Restifo, Linda L. (committeemember), Fuglevand, Andrew (committeemember), Wilson, Jean (committeemember), Gallitano, Amelia (committeemember).
Subjects/Keywords: Congenital Microcephaly;
Cornelia de Lange Syndrome;
MCPH;
Primary Microcephaly;
Seckel Syndrome
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Brown, C. (2017). Genetic Requirements for Building a Brain of Sufficient Size: Insights from Mendelian Congenital Microcephaly Disorders
. (Masters Thesis). University of Arizona. Retrieved from http://hdl.handle.net/10150/625705
Chicago Manual of Style (16th Edition):
Brown, Cecilia. “Genetic Requirements for Building a Brain of Sufficient Size: Insights from Mendelian Congenital Microcephaly Disorders
.” 2017. Masters Thesis, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/625705.
MLA Handbook (7th Edition):
Brown, Cecilia. “Genetic Requirements for Building a Brain of Sufficient Size: Insights from Mendelian Congenital Microcephaly Disorders
.” 2017. Web. 22 Jan 2021.
Vancouver:
Brown C. Genetic Requirements for Building a Brain of Sufficient Size: Insights from Mendelian Congenital Microcephaly Disorders
. [Internet] [Masters thesis]. University of Arizona; 2017. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/625705.
Council of Science Editors:
Brown C. Genetic Requirements for Building a Brain of Sufficient Size: Insights from Mendelian Congenital Microcephaly Disorders
. [Masters Thesis]. University of Arizona; 2017. Available from: http://hdl.handle.net/10150/625705

University of Arizona
11.
Flores, Andrew.
Modulation of Opioid and NMDA Receptors in Preclinical Models of Parkinson’s Disease and Levodopa-Induced Dyskinesia
.
Degree: 2020, University of Arizona
URL: http://hdl.handle.net/10150/648591
► Dopamine (DA)-replacement therapy utilizing L-DOPA is the mainstay of symptomatic treatment for Parkinson’s disease (PD). A critical complication of this therapy is the development of…
(more)
▼ Dopamine (DA)-replacement therapy utilizing L-DOPA is the mainstay of symptomatic treatment for Parkinson’s disease (PD). A critical complication of this therapy is the development of L-DOPA-induced dyskinesia (LID), which occurs in the majority of patients. Endogenous opioid peptides, including enkephalins and dynorphins, are co-transmitters of dopamine, gamma-aminobutyric acid (GABA), and glutamate neurotransmission in the direct and indirect striatal output pathways, which are disrupted in PD. Alterations in levels of expression of these peptides and their precursors have been implicated both in PD and in the subsequent development and expression of LID. Alterations in N-methyl-D-aspartate (NMDA) glutamate transmission have also been implicated in LID; the NMDA receptor antagonist amantadine is the only drug currently approved for the clinical treatment of LID. We utilized pharmacological techniques to investigate the role of altered opioid and NMDA neurotransmission occurring in the direct and indirect striatopallidal output pathways in preclinical models of PD and LID. In the first study presented (Chapter 2), we show that the antidyskinetic effects of the NMDA receptor antagonist MK-801 are preferential to the indirect pathway. Specifically, we show that MK-801 is capable of suppressing hyperkinetic abnormal involuntary movements (AIMs) induced by a selective D2R agonist, quinipirole but not those induced by a selective D1R agonist, SKF81297. Importantly, MK-801 is capable of suppressing AIMs induced by L-DOPA (levodopa, L-3,4-dihydroxyphenylalanine), which is the most effective clinical treatment for PD, even though this agent likely activates both outflow pathways, and quinpirole, but not those induced by SKF81297. This finding of MK-801 also indicates that the contribution of NMDA receptor-mediated glutamatergic transmission to the expression of LID may be specific to the indirect striatopallidal output pathway. In Chapter 3, we have investigated the effects of a novel opioid glycopeptide agonist MMP-2200 which has high affinities and activities for mu and delta opioid receptors on AIMs induced separately by L-DOPA, quinpirole, and SKF81297. We also investigated the combined effects of MMP-2200 and MK-801. It was shown that the opioid glycopeptide MMP-2200 reduced AIMs induced by a D2R selective agonist quinpirole, and MMP-2200 modified the effect of MK-801 to result in a potent reduction of L-DOPA-induced AIMs without induction of parkinsonism. In the studies presented in Chapter 4, we show that the selective kappa opioid receptor antagonist nor-BNI accelerates the rate of development of levodopa-induced AIMs (as opposed to the expression of established AIMs) in a mild striatal 6-OHDA lesion model in a paradigm of chronic gradual dose escalation of L-DOPA to prime LID. Functional restorative effects of nor-BNI on parkinsonian motor deficits were not observed. Together, the studies described here investigated the roles of alterations in NMDA receptor glutamate transmission and opioid peptide transmission…
Advisors/Committee Members: Falk, Torsten (advisor), Sherman, Scott J (advisor), Porreca, Frank (committeemember), Fuglevand, Andrew J. (committeemember), Heien, Michael L. (committeemember).
Subjects/Keywords: Levodopa-induced dyskinesia;
MMP-2200;
NMDA receptor antagonist;
nor-BNI;
Opioid receptors;
Parkinson's disease
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Flores, A. (2020). Modulation of Opioid and NMDA Receptors in Preclinical Models of Parkinson’s Disease and Levodopa-Induced Dyskinesia
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/648591
Chicago Manual of Style (16th Edition):
Flores, Andrew. “Modulation of Opioid and NMDA Receptors in Preclinical Models of Parkinson’s Disease and Levodopa-Induced Dyskinesia
.” 2020. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/648591.
MLA Handbook (7th Edition):
Flores, Andrew. “Modulation of Opioid and NMDA Receptors in Preclinical Models of Parkinson’s Disease and Levodopa-Induced Dyskinesia
.” 2020. Web. 22 Jan 2021.
Vancouver:
Flores A. Modulation of Opioid and NMDA Receptors in Preclinical Models of Parkinson’s Disease and Levodopa-Induced Dyskinesia
. [Internet] [Doctoral dissertation]. University of Arizona; 2020. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/648591.
Council of Science Editors:
Flores A. Modulation of Opioid and NMDA Receptors in Preclinical Models of Parkinson’s Disease and Levodopa-Induced Dyskinesia
. [Doctoral Dissertation]. University of Arizona; 2020. Available from: http://hdl.handle.net/10150/648591

University of Arizona
12.
Mazade, Reece Eric.
Modulation Of Inner Retinal Inhibition With Light Adaptation
.
Degree: 2015, University of Arizona
URL: http://hdl.handle.net/10150/565903
► The retina is able to adjust its signaling over a wide range of light levels. A functional result of this is increased visual acuity at…
(more)
▼ The retina is able to adjust its signaling over a wide range of light levels. A functional result of this is increased visual acuity at brighter luminance levels, such as during the day, due to changes in the organization of retinal receptive fields. This process is commonly referred to as light adaptation. These organizational changes have been shown to occur at the level of the ganglion cells, the output neurons of the retina, which have shifts in their excitatory center-inhibitory surround receptive fields that increase their sensitivity to small stimuli. Recent work supports the idea that light-adapted changes in ganglion cell spatial sensitivity are due in part to inner retinal signaling changes, possibly including changes to inhibition onto bipolar cells, the interneurons at the center of retinal signal processing. However, it is unknown how inhibition to the bipolar cells changes with light adaptation, how any changes affect the light signal or what mediates the changes to the bipolar cells that have been suggested by previous reports. To determine how light adaptation affects bipolar cell inhibition, the inhibitory inputs to OFF bipolar cells were measured. OFF bipolar cells, which respond to the offset of light, in particular may be involved in retinal adaptation as they bridge dim- and bright-light retinal pathways. Their inputs were compared between dark- and light-adapted conditions to determine how any inhibitory changes affects their output onto downstream ganglion cells. We found that there was a compensatory switch from primarily glycinergic-mediated inhibition to OFF bipolar cells in the dark to primarily GABAergic-mediated inhibition in the light. Since glycinergic and GABAergic inhibition perform very different roles and are mediated by morphologically different cells, it is likely this switch underlies a change in the spatial distribution of inhibition to these cells. We found that the spatial inhibitory input to OFF bipolar cells became significantly smaller and narrower with light adaptation, translating to smaller inhibitory surrounds of the OFF bipolar cell receptive fields. Through a model, our data suggested that the OFF bipolar cell output to downstream ganglion cells was stronger in the light, due to the narrowing and reduction in the spatial input, to small light stimuli. This would effectively be one way the retina could use to increase visual acuity. Additionally, we found that the inhibitory changes to OFF bipolar cells with light-adaptation are partially mediated by dopamine D1 receptor signaling. Dopamine is released in the light and has been shown to be an important modulator of retinal light-adaptation. However, there are likely other factors involved in mediating inhibitory changes to OFF bipolar cells. Through these studies, we show that light adaptation heavily influences inner retina inhibition and likely plays a prominent role in determining and shaping light signals under different ambient light conditions which may ultimately be one mechanism for increasing visual…
Advisors/Committee Members: Eggers, Erika D (advisor), Eggers, Erika D. (committeemember), Dussor, Greg (committeemember), Fuglevand, Andrew (committeemember), Levine, Richard (committeemember).
Subjects/Keywords: Bipolar Cell;
Retina;
Physiological Sciences;
Amacrine Cell
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Mazade, R. E. (2015). Modulation Of Inner Retinal Inhibition With Light Adaptation
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/565903
Chicago Manual of Style (16th Edition):
Mazade, Reece Eric. “Modulation Of Inner Retinal Inhibition With Light Adaptation
.” 2015. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/565903.
MLA Handbook (7th Edition):
Mazade, Reece Eric. “Modulation Of Inner Retinal Inhibition With Light Adaptation
.” 2015. Web. 22 Jan 2021.
Vancouver:
Mazade RE. Modulation Of Inner Retinal Inhibition With Light Adaptation
. [Internet] [Doctoral dissertation]. University of Arizona; 2015. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/565903.
Council of Science Editors:
Mazade RE. Modulation Of Inner Retinal Inhibition With Light Adaptation
. [Doctoral Dissertation]. University of Arizona; 2015. Available from: http://hdl.handle.net/10150/565903

University of Arizona
13.
MacNamee, Sarah.
Drosophila melanogaster Astrocytes Respond to and Modulate Synaptic Transmission: A Correlative Anatomical and Electrophysiological Study
.
Degree: 2016, University of Arizona
URL: http://hdl.handle.net/10150/621310
► Astrocytes are the most abundant non-neuronal cells in vertebrate brains. Although Drosophila melanogaster has fewer astrocytic cells relative to neuronal and other glial cell populations,…
(more)
▼ Astrocytes are the most abundant non-neuronal cells in vertebrate brains. Although Drosophila melanogaster has fewer astrocytic cells relative to neuronal and other glial cell populations, they, like vertebrate astrocytes, are located in synaptic regions, organized into exclusive, minimally-overlapping domains, and play developmental roles in synaptogenesis. But, do Drosophila astrocytes have parallel roles in the regulation of synaptic signaling? Preliminary electron microscopic (EM) data indicates that astrocytic processes are located at a greater distance, on average, from Drosophila synapses than they are from vertebrate synapses, thus raising questions about their capacity to alter synaptic signals. Do astrocytic cells and processes occupy stereotyped synaptic regions across repeating segmental structures and across individuals? In the studies presented here, we have addressed these questions directly in the ventral nerve cord (VNC) of the third-instar larva. We collected the first whole-cell patch-clamp recordings from Drosophila astrocytes. These indicate that intrinsic membrane properties, such as low membrane resistance, high capacitance, a hyperpolarized resting potential relative to neurons, a passive current-voltage relationship, coupling to other astrocytic cells, and an absence of voltage-gated currents, are shared between astrocytes of highly divergent species. Next, we optogenetically activated of a group of glutamatergic pre-motor neurons and showed that astrocytes respond with a glutamate transporter current that is mediated by Eaat1, and that acute, pharmacological and chronic, genetic blockades of this transporter have subsequent effects on the decay of post-synaptic motor neuron currents. Then, we used three-dimensional EM to locate the pre-motor glutamatergic neurons that were activated in the physiological study and measured the distance from each presynaptic site to the nearest astrocytic process. We found that these distances vary 100-fold even along a single neurite and that these structures are rarely in direct contact, but that no synapse is positioned greater than one micron from an astrocytic process. Thus, it is in this anatomical configuration that the regulation of post-synaptic currents by Eaat1 occurs. Finally, we generated a library of single, fluorescently-labeled astrocytes that were co-labeled with fiduciary landmarks, and used this library to compare the placement of astrocyte cell bodies and arbors across VNC segments and individuals. We found substantial variation in the gross shape, size, and territory covered by astrocytes, and conclude that their neuropil domains are not reliably stereotyped. Given the consistent placement of neuronal connectome elements, this indicates that signals of a specific synapse are not regulated by a designated astrocyte. Together, these findings reveal new functional parallels between Drosophila and vertebrate astrocytes. These findings argue for the relevance and applicability of mechanistic discovery in Drosophila astrocytes, and set the stage…
Advisors/Committee Members: Oland, Lynne A (advisor), Oland, Lynne A. (committeemember), Fuglevand, Andrew J. (committeemember), Levine, Richard B. (committeemember), Zinsmaier, Konrad E. (committeemember).
Subjects/Keywords: Glia;
Insect;
Invertebrate;
Optogenetics;
Patch Clamp;
Neuroscience;
Electron Microscopy
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
MacNamee, S. (2016). Drosophila melanogaster Astrocytes Respond to and Modulate Synaptic Transmission: A Correlative Anatomical and Electrophysiological Study
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/621310
Chicago Manual of Style (16th Edition):
MacNamee, Sarah. “Drosophila melanogaster Astrocytes Respond to and Modulate Synaptic Transmission: A Correlative Anatomical and Electrophysiological Study
.” 2016. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/621310.
MLA Handbook (7th Edition):
MacNamee, Sarah. “Drosophila melanogaster Astrocytes Respond to and Modulate Synaptic Transmission: A Correlative Anatomical and Electrophysiological Study
.” 2016. Web. 22 Jan 2021.
Vancouver:
MacNamee S. Drosophila melanogaster Astrocytes Respond to and Modulate Synaptic Transmission: A Correlative Anatomical and Electrophysiological Study
. [Internet] [Doctoral dissertation]. University of Arizona; 2016. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/621310.
Council of Science Editors:
MacNamee S. Drosophila melanogaster Astrocytes Respond to and Modulate Synaptic Transmission: A Correlative Anatomical and Electrophysiological Study
. [Doctoral Dissertation]. University of Arizona; 2016. Available from: http://hdl.handle.net/10150/621310

University of Arizona
14.
Laine, Christopher.
Decoding the Language of Hypoglossal Motor Control
.
Degree: 2011, University of Arizona
URL: http://hdl.handle.net/10150/203440
► To effect movement, the central nervous system must appropriately coordinate the activities of pools of motoneurons (MNs), the cells which control muscle fibers. Sources of…
(more)
▼ To effect movement, the central nervous system must appropriately coordinate the activities of pools of motoneurons (MNs), the cells which control muscle fibers. Sources of neural drive are often distributed to many MNs of a pool, and thus can synchronize the activities of targeted MNs. In this thesis, synchronization among MNs is used to investigate the strength, temporal progression, and anatomical distribution of neural drive to the hypoglossal motor nucleus (HMN), which controls muscles of the tongue. The HMN is an ideal target for such an investigation because it processes a host of functionally diverse inputs, such as those related to breathing, speaking, and swallowing. Study 1 characterizes motor unit (MU) synchronization within and across bellies of the human genioglossus (GG) muscle when MUs are activated by cortical drive (during voluntary tongue protrusion) or by automatic, brainstem-mediated drive (during rest breathing). We show that voluntary tongue protrusion synchronizes MU spike timing and firing rates within but not across bellies of the GG, whereas during rest breathing, MU firing rates are moderately synchronized both within and across muscle bellies. Study 2 documents respiratory-related synchronization of MU activities in muscles of the tongue and respiratory pump using an anesthetized rat model. The results of this study indicate that upper airway and respiratory pump MN pools share a low frequency respiratory-related drive, but that higher frequency (>8 Hz) synchronization is strongest in MU pairs of the chest-wall. Finally, Study 3 examines the potential for GG multi-unit and single MU activities to be entrained by cortical input. We show that during voluntary tongue protrusion, cortical oscillations in the 15-40 Hz range weakly synchronize MU population activity, and that EEG oscillations in this range intermittently influence the spike timing of individual GG MUs. These studies are the first to characterize MU synchronization by different sources of neural input to the HMN and establish a broad foundation for further investigation of hypoglossal motor control.
Advisors/Committee Members: Bailey, E. Fiona (advisor), Levine, Richard (committeemember), Fregosi, Ralph (committeemember), Fellous, Jean-Marc (committeemember), Bailey, E. Fiona (committeemember), Fuglevand, Andrew (committeemember).
Subjects/Keywords: genioglossus;
hypoglossal;
motoneuron;
Motor Unit;
Physiological Sciences;
EEG;
EMG
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Laine, C. (2011). Decoding the Language of Hypoglossal Motor Control
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/203440
Chicago Manual of Style (16th Edition):
Laine, Christopher. “Decoding the Language of Hypoglossal Motor Control
.” 2011. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/203440.
MLA Handbook (7th Edition):
Laine, Christopher. “Decoding the Language of Hypoglossal Motor Control
.” 2011. Web. 22 Jan 2021.
Vancouver:
Laine C. Decoding the Language of Hypoglossal Motor Control
. [Internet] [Doctoral dissertation]. University of Arizona; 2011. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/203440.
Council of Science Editors:
Laine C. Decoding the Language of Hypoglossal Motor Control
. [Doctoral Dissertation]. University of Arizona; 2011. Available from: http://hdl.handle.net/10150/203440

University of Arizona
15.
Mosher, Clayton Paul.
Neurons In The Monkey Amygdala Detect Eye Contact During Naturalistic Social Interactions
.
Degree: 2014, University of Arizona
URL: http://hdl.handle.net/10150/332845
► Eye contact is a fundamental means of social interaction among primates. In both humans and non-human primate societies, eye contact precedes and signals aggression or…
(more)
▼ Eye contact is a fundamental means of social interaction among primates. In both humans and non-human primate societies, eye contact precedes and signals aggression or prosocial behaviors. Initiating and maintaining short periods of eye contact is essential during social interactions that build trust and promote cooperation. How the brain detects and orchestrates social exchanges mediated by eye contact remains an open question in neuroscience. Theories of social neuroscience speculate that the social brain in primates contains neurons specialized to detect and respond to eye-contact. This dissertation reports the discovery and characterization of a class of neurons, located in the amygdala of monkeys, that is activated selectively during eye contact. The discovery of these cells was facilitated by (1) characterization of the response properties of neurons in the amygdala during a canonical image-viewing task and (2) development of a reliable and quantifiable method for eliciting naturalistic eye contact between monkeys in the laboratory setting. The functional role of eye contact cells remains to be determined. The data presented in this dissertation confirm the role of the amygdala in social behaviors and allows for the formulation of new hypotheses about the cellular mechanisms within the amygdala that support complex social interactions among primates.
Advisors/Committee Members: Gothard, Katalin M (advisor), Gothard, Katalin M. (committeemember), Fuglevand, Andrew J. (committeemember), Zinsmaier, Konrad E. (committeemember), Watkins, Joseph C. (committeemember).
Subjects/Keywords: eye contact;
primate;
single unit activity;
social neuroscience;
Neuroscience;
amygdala
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
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APA (6th Edition):
Mosher, C. P. (2014). Neurons In The Monkey Amygdala Detect Eye Contact During Naturalistic Social Interactions
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/332845
Chicago Manual of Style (16th Edition):
Mosher, Clayton Paul. “Neurons In The Monkey Amygdala Detect Eye Contact During Naturalistic Social Interactions
.” 2014. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/332845.
MLA Handbook (7th Edition):
Mosher, Clayton Paul. “Neurons In The Monkey Amygdala Detect Eye Contact During Naturalistic Social Interactions
.” 2014. Web. 22 Jan 2021.
Vancouver:
Mosher CP. Neurons In The Monkey Amygdala Detect Eye Contact During Naturalistic Social Interactions
. [Internet] [Doctoral dissertation]. University of Arizona; 2014. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/332845.
Council of Science Editors:
Mosher CP. Neurons In The Monkey Amygdala Detect Eye Contact During Naturalistic Social Interactions
. [Doctoral Dissertation]. University of Arizona; 2014. Available from: http://hdl.handle.net/10150/332845

University of Arizona
16.
Powell, Gregory Leverette.
Developmental Nicotine Exposure And Its Effects On Morphology And Electrophysiology Of Hypoglossal Motoneurons In The Neonatal Rat
.
Degree: 2014, University of Arizona
URL: http://hdl.handle.net/10150/337298
► Developmental nicotine exposure (DNE) is known to cause deleterious effects in neonatal mammals through nicotine's actions on nicotinic acetylcholine receptors (nAChRs). In this work, we…
(more)
▼ Developmental nicotine exposure (DNE) is known to cause deleterious effects in neonatal mammals through nicotine's actions on nicotinic acetylcholine receptors (nAChRs). In this work, we studied how DNE altered the structure and function of the hypoglossal motoneurons (XIIMNs) over the first few days post-parturition. Previous work in XIIMNs demonstrated an increase in cellular excitability (Pilarski et al., 2011), alterations in synaptic transmission among respiratory-related neurons (Wang et al., 2006; Pilarski et al., 2012; Jaiswal et al., 2013), and a reduction in inspiratory drive currents in DNE animals (Pilarski et al., 2011). Here we show that the effects of DNE extend to alterations in the spike-timing precision and reliability of XIIMNs, as well as spike-frequency adaptation. Additionally, simple morphological analysis of XIIMNs following nicotine exposure in utero has revealed a reduction in soma cross-sectional area. We were interested in studying the complete morphology of XIIMNs following DNE to discern its effects on more complex morphological parameters. We advanced this research using a combination of techniques in thin brainstem slices of neonatal rats, including whole cell patch clamp recordings and immunohistochemistry of intracellularly labeled hypoglossal motoneurons. Furthermore, morphological analysis revealed significant differences in the complexity of the dendritic arborization, showing that neurons from DNE animals had shorter dendrites that branched less often. We also used computational analysis to gain insight into mechanisms that may underlie the changes in spike-timing precision and reliability. In a single cell model of XIIMNs, decreases in potassium-dependent conductances such as the calcium-activated potassium current could potentially replicate the alterations seen in vitro. Finally, we also did a systems-level study of the hyoglossus muscle, a tongue retractor, to determine the relation between tongue retraction force and motor unit discharge characteristics. These experiments utilized adult, anesthetized rats to record single motor units, whole muscle electromyography (EMG) activity and tongue retraction force during spontaneous breathing. We determined that during inspiration-related tongue retractions in low and high force conditions, recruitment of motor units plays a crucial role in the control of tongue force output, whereas rate coding of single motor units is present, but appears to play a lesser role. Overall, this study shows that DNE effects the input-output properties of XIIMNs, potentially through changes in intrinsic channel properties; DNE also alters XIIMN morphology, particularly dendritic arborization; and that organization of a tongue retractor muscle depends primarily on recruitment, but also rate coding, to increase force output.
Advisors/Committee Members: Fregosi, Ralph F (advisor), Fregosi, Ralph F. (committeemember), Levine, Richard (committeemember), Fuglevand, Andrew (committeemember), Fellous, Jean-Marc (committeemember), Secomb, Timothy (committeemember).
Subjects/Keywords: Development;
Hypoglossal;
Motoneuron;
Motor Unit;
Nicotine;
Breathing;
Physiological Sciences
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Powell, G. L. (2014). Developmental Nicotine Exposure And Its Effects On Morphology And Electrophysiology Of Hypoglossal Motoneurons In The Neonatal Rat
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/337298
Chicago Manual of Style (16th Edition):
Powell, Gregory Leverette. “Developmental Nicotine Exposure And Its Effects On Morphology And Electrophysiology Of Hypoglossal Motoneurons In The Neonatal Rat
.” 2014. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/337298.
MLA Handbook (7th Edition):
Powell, Gregory Leverette. “Developmental Nicotine Exposure And Its Effects On Morphology And Electrophysiology Of Hypoglossal Motoneurons In The Neonatal Rat
.” 2014. Web. 22 Jan 2021.
Vancouver:
Powell GL. Developmental Nicotine Exposure And Its Effects On Morphology And Electrophysiology Of Hypoglossal Motoneurons In The Neonatal Rat
. [Internet] [Doctoral dissertation]. University of Arizona; 2014. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/337298.
Council of Science Editors:
Powell GL. Developmental Nicotine Exposure And Its Effects On Morphology And Electrophysiology Of Hypoglossal Motoneurons In The Neonatal Rat
. [Doctoral Dissertation]. University of Arizona; 2014. Available from: http://hdl.handle.net/10150/337298

University of Arizona
17.
Szabo, Zoltan.
Analysis of Tactile, and Audio-Tactile Display-Based Regulatory Human-in-the-Loop Control Systems
.
Degree: 2019, University of Arizona
URL: http://hdl.handle.net/10150/636523
► Throughout history a great variety of tasks has involved the utilization of a combination of mechanical or electromechanical equipment and a human operator. These tasks…
(more)
▼ Throughout history a great variety of tasks has involved the utilization of a combination of mechanical or electromechanical equipment and a human operator. These tasks range from simple activities such as using a hammer to install a nail to complicated maneuvers executed by fighter plane pilots. The inherent interdependence of humans and machines forms a closed loop control system known as the human-in-the-loop control system. The objective of the system is to complete a task within certain limitations, such as time, imposed by operating requirements. In modern times, artificially created guidance signals provide feedback to the human user to guide him or her in executing the desired task in an optimal manner. The most frequently used guidance is based on visual cues such as lights and monitors. Its role has been studies by a great many researchers as its applicability is trivial due to its intuitive nature. In certain situations however, visual guidance cannot be provided and humans may need to rely on proprioception, auditory or tactile guidance. While application examples of tactile and audio-tactile support have been known, their optimal selection of operating parameters and humans’ behavior in response to receiving these signals have been disproportionately understudied. Current dissertation aims at identifying the parameters and efficiency of vibrotactile and audio-vibrotactile feedback signals in their ability to provide guidance in human-in-the-loop control systems. This work also sets out to describe human behavior in response to these guiding signals. In possession of the understanding of human behavior, development of an active controller is targeted with the goal to further optimize human performance. The Chapters 1 and 2 of the dissertation review the literature related to human-in-the-loop control systems and the various guiding signals used in these systems. Chapter 3 presents the research questions and hypotheses, while Chapter 4 outlines the necessary experiments to analyze the research questions. Chapter 5 presents a custom made, state of the art device, its utilization throughout various 1 and 3 dimensional target seeking experiments is discussed through Chapters 6-9. The setup, results and discussion of the experiments lead to conclusions regarding the fundamental research questions. Final conclusions are summarized in Chapter 10. A review of potential application examples is included in Chapter 11 while a proposal for future research is presented in Chapter 12. Analysis of experiment results reveals that the best performing displays utilize audio-tactile technology, where the indication of reaching the target position is signaled by an auditory beep. The seconds best performing group of displays provide tactile-only guidance, wherein the on-target position is indicated by the lack of tactile feedback. The bottom of the ranking list is populated by tactile-only displays which provide no differentiated signal when the subject reaches target. These results apply to both 1 and 3 signal channel…
Advisors/Committee Members: Enikov, Eniko T (advisor), Wilson, Robert (committeemember), Reverdy, Paul (committeemember), Fuglevand, Andrew J. (committeemember), Arabyan, Ara (committeemember).
Subjects/Keywords: behavior primitive;
control system;
haptic;
human factors;
human-in-the-loop;
tactile
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Szabo, Z. (2019). Analysis of Tactile, and Audio-Tactile Display-Based Regulatory Human-in-the-Loop Control Systems
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/636523
Chicago Manual of Style (16th Edition):
Szabo, Zoltan. “Analysis of Tactile, and Audio-Tactile Display-Based Regulatory Human-in-the-Loop Control Systems
.” 2019. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/636523.
MLA Handbook (7th Edition):
Szabo, Zoltan. “Analysis of Tactile, and Audio-Tactile Display-Based Regulatory Human-in-the-Loop Control Systems
.” 2019. Web. 22 Jan 2021.
Vancouver:
Szabo Z. Analysis of Tactile, and Audio-Tactile Display-Based Regulatory Human-in-the-Loop Control Systems
. [Internet] [Doctoral dissertation]. University of Arizona; 2019. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/636523.
Council of Science Editors:
Szabo Z. Analysis of Tactile, and Audio-Tactile Display-Based Regulatory Human-in-the-Loop Control Systems
. [Doctoral Dissertation]. University of Arizona; 2019. Available from: http://hdl.handle.net/10150/636523

University of Arizona
18.
Vranish, Jennifer R.
Obstructive Sleep Apnea: Daytime Assessment And Treatment Of A Nighttime Disorder
.
Degree: 2015, University of Arizona
URL: http://hdl.handle.net/10150/566239
► Obstructive sleep apnea (OSA) is a disease characterized by nighttime airflow limitation, hypoxemia, arousal from sleep, and elevated sympathetic activity and blood pressure. With time,…
(more)
▼ Obstructive sleep apnea (OSA) is a disease characterized by nighttime airflow limitation, hypoxemia, arousal from sleep, and elevated sympathetic activity and blood pressure. With time, this nighttime dysfunction gives rise to daytime hypertension and a heightened risk for cardiovascular disease. Current treatment options for OSA are not always effective for all patients and the gold-standard intervention, continuous positive airway pressure, has discouraging compliance rates. The work set forth in this dissertation has as its focus a novel intervention for sleep apnea known as inspiratory muscle training (IMT). IMT improves respiratory function and cardiovascular health but has not been implemented previously as a treatment for OSA. As such, Study 1 implements IMT in individuals with mild and moderate OSA, with the objective of assessing the effects of training on the cardio- respiratory parameters of this disease. We randomly assigned 24 individuals with mild- moderate OSA into one of two groups: training vs. placebo, to assess the effects of 6 weeks of training on overnight polysomnography, subjective sleep quality, blood pressure, circulating inflammatory T cells, and plasma catecholamine content. Our results show IMT- related improvements in sleep quality, reduction in the number of arousals from sleep and in periodic limb movements following 6 weeks of training. Most important, IMT was associated with a significant reduction in systolic (~12 mmHg) and diastolic (~5 mmHg) blood pressure, relative to sleep apneics who undertook 6 weeks of placebo training. Additionally, individuals in the training group exhibited ~30% lower levels of sympathetic activity, as measured by plasma catecholamines, relative to placebo trained peers. The mechanism(s) that underlie the IMT-related reductions in blood pressure and sympathetic activity remain to be determined. However, in an effort to determine the precise respiratory stimulus that contributes to the results obtained in Study 1, we subsequently assessed the specific respiratory components of IMT to determine which component (large intrathoracic pressures and/or large lung volumes) likely contributes to the reduction in blood pressure in Study 1. The results of this study conducted in normotensive adults show that respiratory training that entails either large negative or positive intrathoracic pressures reduces systolic and diastolic blood pressure in healthy young adults. Importantly, neither the generation of large lung volumes alone nor performance of daily paced breathing is sufficient to lower blood pressure. Study 3 is a methodologic study that has as its focus upper airway electromyography (EMG) and the utility of assessing EMG activity across a range of conditions and breathing tasks in wakefulness. Because OSA traditionally has been viewed as the result of neuromuscular dysfunction of the upper airway that occurs during sleep, the aim of this work was to develop a "fingerprint" of healthy electromyographic activities during the day in healthy adults across a range…
Advisors/Committee Members: Bailey, Elizabeth Fiona (advisor), Bailey, Elizabeth Fiona (committeemember), Fregosi, Ralph F. (committeemember), Fuglevand, Andrew J. (committeemember), Konhilas, John P. (committeemember), Levine, Richard B. (committeemember).
Subjects/Keywords: Inspiratory Training;
Sleep Apnea;
Physiological Sciences;
Blood Pressure
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Vranish, J. R. (2015). Obstructive Sleep Apnea: Daytime Assessment And Treatment Of A Nighttime Disorder
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/566239
Chicago Manual of Style (16th Edition):
Vranish, Jennifer R. “Obstructive Sleep Apnea: Daytime Assessment And Treatment Of A Nighttime Disorder
.” 2015. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/566239.
MLA Handbook (7th Edition):
Vranish, Jennifer R. “Obstructive Sleep Apnea: Daytime Assessment And Treatment Of A Nighttime Disorder
.” 2015. Web. 22 Jan 2021.
Vancouver:
Vranish JR. Obstructive Sleep Apnea: Daytime Assessment And Treatment Of A Nighttime Disorder
. [Internet] [Doctoral dissertation]. University of Arizona; 2015. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/566239.
Council of Science Editors:
Vranish JR. Obstructive Sleep Apnea: Daytime Assessment And Treatment Of A Nighttime Disorder
. [Doctoral Dissertation]. University of Arizona; 2015. Available from: http://hdl.handle.net/10150/566239
19.
Bagnoli, Brenden C.
Auditory Information Processing and Functional Correlates
.
Degree: 2019, University of Arizona
URL: http://hdl.handle.net/10150/632979
► Many adults report difficulty understanding speech in the presence of competing noise in spite of having normal audiometric thresholds. Possible factors contributing to this variability…
(more)
▼ Many adults report difficulty understanding speech in the presence of competing noise in spite of having normal audiometric thresholds. Possible factors contributing to this variability in perceived speech in noise (SPIN) performance are auditory mechanisms such as temporal processing and dichotic listening, as well as supramodal processes of attention and working memory. Clinically, behavioral tests are used to assess SPIN performance, but self-report questionnaires provide an alternative way to identify specific listening deficits. The goal of this study is to explore the variability observed among a number of different measures of auditory processing, the correspondence between the measures, and to identify underlying factors that contribute to overall speech-in-noise performance in a group of normal hearing individuals (n=20). A combination of behavioral tests and self-report questionnaires were administered. Principal Component analysis was used to examine the variability observed in the total set of measures and reduce the variability to a smaller set of factors. Factor analysis revealed six extracted components accounting for 81% of total variance that were determined to represent “Working Memory”, “Temporal Processing”, “Dichotic Listening”, “Anxiety”, “Self-Report Deficits”, and possibly “Concentration”. It was determined that working memory is a likely underlying factor affecting clinical speech in noise test performance in this sample of individuals. Additionally it was discovered that self-report questionnaires do not “co-load” onto components with behavioral measures, revealing that they are assessing different elements of auditory function and add value to test batteries.
Advisors/Committee Members: Velenovsky, David (advisor), Norrix, Linda (committeemember), Dean, James (committeemember), Fuglevand, Andrew (committeemember).
…sensitivity were recruited using
flyers (Appendix A) posted in the University of Arizona… …from The Institutional Review Board of the University of
Arizona.
15
Tests Administered…
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Bagnoli, B. C. (2019). Auditory Information Processing and Functional Correlates
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/632979
Chicago Manual of Style (16th Edition):
Bagnoli, Brenden C. “Auditory Information Processing and Functional Correlates
.” 2019. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/632979.
MLA Handbook (7th Edition):
Bagnoli, Brenden C. “Auditory Information Processing and Functional Correlates
.” 2019. Web. 22 Jan 2021.
Vancouver:
Bagnoli BC. Auditory Information Processing and Functional Correlates
. [Internet] [Doctoral dissertation]. University of Arizona; 2019. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/632979.
Council of Science Editors:
Bagnoli BC. Auditory Information Processing and Functional Correlates
. [Doctoral Dissertation]. University of Arizona; 2019. Available from: http://hdl.handle.net/10150/632979
20.
Morrow, Jeremiah Kegley.
Multisensory Processing in the Primate Amygdala
.
Degree: 2019, University of Arizona
URL: http://hdl.handle.net/10150/634381
► The ability to make use of the diverse sensory information present in the natural world is critical for every living creature from single-cell organisms to…
(more)
▼ The ability to make use of the diverse sensory information present in the natural world is critical for every living creature from single-cell organisms to humans. In the primate brain, signals from different sensory modalities begin to intermix as early as the primary sensory cortices and become intricately interwoven along a myriad of parallel processing routes. Many of these routes pass through a temporal lobe structure called the amygdala. This subcortical cluster of nuclei is involved in a host of functions ranging from regulation of the autonomic nervous system to the generation of social behaviors. Despite the diverse inputs and varied functions of the amygdala, most of what is known about this structure in primates comes from studies that relied on visual stimuli. More must be done to assess how the primate amygdala processes multisensory information in order to better understand how this structure contributes to higher order cognitive functions. The three chapters of this dissertation report the outcome of experiments that are a logical progression of my research.
The first experiment presented here examined how the amygdala processes visual information as monkeys scanned complex arrays of images. While some theories suggested that neural activity in the amygdala should alert an organism to potentially important stimuli before the animal attends to them, we found that the activity of neurons in the amygdala was gated by attention. Some neurons were found to be tuned to specific categories of stimuli (e.g., monkey faces or flowers); however, many cells responded to some degree across a range of categories. The complexity of the responses seen in this study have become increasingly common observations in neuroscience experiments.
In order to link the work in the visual domain with ongoing work in the laboratory that focused on touch, we designed an experiment that involved both visual and tactile stimuli. We also added auditory stimuli in order to cover a wider subset of sensory domains. In these experiments, we examined the responses of neurons in the amygdala to stimuli that were devoid of any obvious emotional or social meaning to the monkeys (neurons in the amygdala are known to respond to these abstract features). As expected, we found neurons that responded to stimuli of all three sensory domains; however, we were surprised by the large proportion of responsive cells (~70%) given the low salience of the stimuli. Furthermore, we found that many neurons appeared to differentiate the sensory modality of the stimulus by varying different parameters of their spiking activity. The high number of multisensory responses from neurons in the amygdala suggests that researchers may be missing many crucial functions of this structure when the stimulus space is small or focuses on stimuli from a single sensory domain. The second chapter of the dissertation reports the outcome of this experiment.
In the third chapter, I report the outcome of applying a data analysis method, new to the study of local field potentials…
Advisors/Committee Members: Gothard, Katalin M (advisor), Fuglevand, Andrew (committeemember), Barnes, Carol (committeemember), Cai, Haijiang (committeemember).
Subjects/Keywords: Amygdala;
Electrophysiology;
Primate;
Social
…University of Arizona (including Dr. Katalin
Gothard, then senior graduate student Clayton… …however, work at the University of Arizona (including my own) focused
on the non-human… …at the University of Arizona. We performed single-neuron recordings as previously
reported…
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Morrow, J. K. (2019). Multisensory Processing in the Primate Amygdala
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/634381
Chicago Manual of Style (16th Edition):
Morrow, Jeremiah Kegley. “Multisensory Processing in the Primate Amygdala
.” 2019. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/634381.
MLA Handbook (7th Edition):
Morrow, Jeremiah Kegley. “Multisensory Processing in the Primate Amygdala
.” 2019. Web. 22 Jan 2021.
Vancouver:
Morrow JK. Multisensory Processing in the Primate Amygdala
. [Internet] [Doctoral dissertation]. University of Arizona; 2019. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/634381.
Council of Science Editors:
Morrow JK. Multisensory Processing in the Primate Amygdala
. [Doctoral Dissertation]. University of Arizona; 2019. Available from: http://hdl.handle.net/10150/634381

University of Arizona
21.
Seifert, Heather.
Restoration of Finger Movement using Functional Electrical Stimulation and Bayes' Theorem
.
Degree: 2001, University of Arizona
URL: http://hdl.handle.net/10150/633309
► Various computational approaches have been applied to predict aspects of animal behavior from the recorded activity of populations of neurons. Here we invert this process…
(more)
▼ Various computational approaches have been applied to predict aspects of animal behavior from the recorded activity of populations of neurons. Here we invert this process to predict the requisite neuromuscular activity associated with specified motor behaviors. A probabilistic method based on Bayes' theorem was used to predict the patterns of muscular activity needed to produce various types of desired finger movements. The profiles of predicted activity were then used to drive frequencymodulated muscle stimulators in order to evoke multi-joint finger movements. Comparison of movements generated by electrical stimulation to desired movements yielded root mean squared errors between -18 - 26%. This reasonable correspondence between desired and evoked movements suggests that this approach might serve as a useful strategy to control neuroprosthetic systems that aim to restore movement to paralyzed individuals.
Advisors/Committee Members: Fuglevand, Andrew (advisor), (committeemember).
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Seifert, H. (2001). Restoration of Finger Movement using Functional Electrical Stimulation and Bayes' Theorem
. (Masters Thesis). University of Arizona. Retrieved from http://hdl.handle.net/10150/633309
Chicago Manual of Style (16th Edition):
Seifert, Heather. “Restoration of Finger Movement using Functional Electrical Stimulation and Bayes' Theorem
.” 2001. Masters Thesis, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/633309.
MLA Handbook (7th Edition):
Seifert, Heather. “Restoration of Finger Movement using Functional Electrical Stimulation and Bayes' Theorem
.” 2001. Web. 22 Jan 2021.
Vancouver:
Seifert H. Restoration of Finger Movement using Functional Electrical Stimulation and Bayes' Theorem
. [Internet] [Masters thesis]. University of Arizona; 2001. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/633309.
Council of Science Editors:
Seifert H. Restoration of Finger Movement using Functional Electrical Stimulation and Bayes' Theorem
. [Masters Thesis]. University of Arizona; 2001. Available from: http://hdl.handle.net/10150/633309

University of Arizona
22.
Keen, Douglas Andrew.
Neural and muscular control of the human extensor digitorum muscle
.
Degree: 2002, University of Arizona
URL: http://hdl.handle.net/10150/280191
► The human hand has incredible dexterity which depends, in large part, on the ability to move the fingers relatively independently. Interestingly, many of the primary…
(more)
▼ The human hand has incredible dexterity which depends, in large part, on the ability to move the fingers relatively independently. Interestingly, many of the primary finger flexor and extensor muscles possess a single belly that gives rise distally to multiple tendons that insert onto all the fingers and consequently might produce movement in all of the fingers. Therefore, the objective of this dissertation was to examine the neuromuscular organization of a multi-tendoned finger extensor muscle, the human extensor digitorum (ED). Initially, we found that ED spike-triggered average motor unit force was broadly distributed across the digits. Consequently, we hypothesized that linkages between the distal tendons of ED may cause force developed in a single compartment to be transmitted to neighboring tendons. However, force arising from intramuscular stimulation was fairly focused to a single digit suggesting that inter-tendonous connections account for little of the broad distribution of motor unit force. An alternative possibility was that our spike-triggered averages of motor unit force were contaminated by correlated activity among motor units residing in different compartments. Strong motor unit synchrony was found for motor unit pairs within compartments and a modest degree of synchrony for motor unit pairs in neighboring compartments which likely contributed to the appearance of spike-triggered average motor unit force on multiple fingers. These results suggest that last-order synaptic projections appear to supply predominantly sub-sets of motor neurons innervating specific finger compartments of ED but also branch to supply motor neurons innervating other compartments. Finally, single motor axons branch to innervate muscle fibers situated in multiple compartments of ED. Interestingly, force resulting from intraneural micro stimulation of single motor axons innervating ED was highly focused to a single digit. Therefore, it appears that the muscle fibers innervated by a motor axon are primarily confined to one of four distinct compartments of ED. Based on these experiments we believe that each finger is acted upon by ED through a discreet population of motor units. Consequently, extension of an individual finger would require the selective activation of motor neurons innervating a specific compartment of ED.
Advisors/Committee Members: Fuglevand, Andrew J (advisor).
Subjects/Keywords: Biology; Neuroscience.
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Keen, D. A. (2002). Neural and muscular control of the human extensor digitorum muscle
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/280191
Chicago Manual of Style (16th Edition):
Keen, Douglas Andrew. “Neural and muscular control of the human extensor digitorum muscle
.” 2002. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/280191.
MLA Handbook (7th Edition):
Keen, Douglas Andrew. “Neural and muscular control of the human extensor digitorum muscle
.” 2002. Web. 22 Jan 2021.
Vancouver:
Keen DA. Neural and muscular control of the human extensor digitorum muscle
. [Internet] [Doctoral dissertation]. University of Arizona; 2002. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/280191.
Council of Science Editors:
Keen DA. Neural and muscular control of the human extensor digitorum muscle
. [Doctoral Dissertation]. University of Arizona; 2002. Available from: http://hdl.handle.net/10150/280191
23.
Thome, Alexander.
Experience-Dependent Network Modification in the Medial Temporal Lobe
.
Degree: 2012, University of Arizona
URL: http://hdl.handle.net/10150/223358
► Theoretical models of information storage in the brain have suggested that neurons may undergo an experience-dependent tuning or sharpening of their representations in order to…
(more)
▼ Theoretical models of information storage in the brain have suggested that neurons may undergo an experience-dependent tuning or sharpening of their representations in order to maximize the amount of information that can be stored. Changes in the tuning profiles of neurons have been demonstrated to occur when animals must learn perceptual discriminations, however, whether similar changes occur in the absence of behavioral demands is unclear. To address these questions, the activity of simultaneously recorded medial temporal lobe (MTL) neurons was studied in relation to a passive visual recognition memory task. The structure of this task was such that it allowed for a comparison between novelty related responses as well as tuning properties of individual neurons. A total of 565 well isolated single neurons were recorded. The first contribution of this dissertation is the finding of a dissociation between different medial temporal lobe regions such that neurons in temporal area F (TF), but not perirhinal cortex (PRC) or the hippocampus, show an experience-dependent change in their stimulus selectivity. This finding indicates that tuning of stimulus representations may be an effective mechanism for maximizing information storage in some brain regions. The absence of stimulus tuning in higher level association regions (i.e. TF and PRC) suggests that tuning in these regions may be disadvantageous due to the need to construct unified representations across sensory modalities. A complimentary question to the question of network storage capacity is how networks avoid saturation in the connections between neurons. The second contribution of this dissertation is the finding that there exists a decrease in the magnitude of the short time scale correlations between pairs of neurons; suggesting that networks reduce the number of connections between neurons as a stimulus becomes familiar. Gamma oscillations have been proposed to be the mechanism by which groups of neurons coordinate their activity. However, network coordination has only been indirectly measured. The final contribution of this dissertation is the finding that the magnitude of gamma oscillations is strongly correlated with enhanced magnitude of correlations between neurons.
Advisors/Committee Members: Barnes, Carol A (advisor), Nadel, Lynn (committeemember), Gothard, Katalin (committeemember), Fuglevand, Andrew (committeemember), Zinsmaier, Konrad (committeemember), Barnes, Carol A. (committeemember).
Subjects/Keywords: Memory;
Single-Unit;
Neuroscience;
Correlations;
Medial Temporal Lobe
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Thome, A. (2012). Experience-Dependent Network Modification in the Medial Temporal Lobe
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/223358
Chicago Manual of Style (16th Edition):
Thome, Alexander. “Experience-Dependent Network Modification in the Medial Temporal Lobe
.” 2012. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/223358.
MLA Handbook (7th Edition):
Thome, Alexander. “Experience-Dependent Network Modification in the Medial Temporal Lobe
.” 2012. Web. 22 Jan 2021.
Vancouver:
Thome A. Experience-Dependent Network Modification in the Medial Temporal Lobe
. [Internet] [Doctoral dissertation]. University of Arizona; 2012. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/223358.
Council of Science Editors:
Thome A. Experience-Dependent Network Modification in the Medial Temporal Lobe
. [Doctoral Dissertation]. University of Arizona; 2012. Available from: http://hdl.handle.net/10150/223358
24.
Jaiswal, Stuti J.
The Consequences of Developmental Nicotine Exposure on Neonatal Central Respiratory Control
.
Degree: 2013, University of Arizona
URL: http://hdl.handle.net/10150/293608
► Developmental nicotine exposure (DNE) exerts negative consequences on the CNS via the activation of nAChRs that are available early and widely throughout development (refs). In…
(more)
▼ Developmental nicotine exposure (DNE) exerts negative consequences on the CNS via the activation of nAChRs that are available early and widely throughout development (refs). In this work, we examined how DNE changed excitatory and inhibitory neurotransmission in brainstem regions involved in central breathing control. Previous work using the brainstem-spinal cord preparation had shown that DNE augmented the respiratory-related response to AMPA, muscimol (a GABAA agonist), and glycine (Luo et al., 2004; Luo et al., 2007; Pilarski and Fregosi, 2009a). These studies used a split-bath preparation in which a drug (AMPA, muscimol, or glycine) was applied to medulla, and the frequency of the respiratory response (in the form of spontaneous, rhythmic bursting activity) was recorded from cervical nerve 4 (C4), which provides output to the diaphragm. Although these studies showed that DNE AMPA, GABA(A), and glycine neurotransmission in the medulla, the regions mediating the effect and the mechanism of DNE's action remained unclear. In this study we tested the hypothesis that the observed changes in respiratory burst frequency were mediated through the preBötzinger complex (preBötC), and the mechanism of enhanced activity involved an upregulation of neurotransmitter receptors. Additionally, we were interested in studying the effect of DNE on breathing-related motor pools, and therefore studied DNE's effect on excitatory and inhibitory neurotransmission in the XIIMN. We approached these questions and aims using a combination of techniques, including extracellular recordings from whole nerve output in rhythmic brainstem slices, immunohistochemistry, and Western blotting. We found enhanced AMPA, GABA(A), and glycine neurotransmission in the XIIMN and preBötC, and varying changes in neurotransmitter receptor expression in both groups. Additionally, we found a decrease in motoneuron soma size in XII motoneurons that stained positively for the glycine receptor. Overall, this study shows that DNE alters inhibitory and excitatory neurotransmission in both the preBötC and XIIMN, and that these changes may be mediated through a combination of change in cell size and receptor expression.
Advisors/Committee Members: Fregosi, Ralph F (advisor), Bailey, Elizabeth Fiona (committeemember), Fuglevand, Andrew (committeemember), Levine, Richard (committeemember), Henriksen, Erik (committeemember).
Subjects/Keywords: breathing;
nicotine;
Neuroscience;
brainstem
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Jaiswal, S. J. (2013). The Consequences of Developmental Nicotine Exposure on Neonatal Central Respiratory Control
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/293608
Chicago Manual of Style (16th Edition):
Jaiswal, Stuti J. “The Consequences of Developmental Nicotine Exposure on Neonatal Central Respiratory Control
.” 2013. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/293608.
MLA Handbook (7th Edition):
Jaiswal, Stuti J. “The Consequences of Developmental Nicotine Exposure on Neonatal Central Respiratory Control
.” 2013. Web. 22 Jan 2021.
Vancouver:
Jaiswal SJ. The Consequences of Developmental Nicotine Exposure on Neonatal Central Respiratory Control
. [Internet] [Doctoral dissertation]. University of Arizona; 2013. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/293608.
Council of Science Editors:
Jaiswal SJ. The Consequences of Developmental Nicotine Exposure on Neonatal Central Respiratory Control
. [Doctoral Dissertation]. University of Arizona; 2013. Available from: http://hdl.handle.net/10150/293608
25.
Navratilova, Zaneta.
The Role of Path Integration on Neural Activity in Hippocampus and Medial Entorhinal Cortex
.
Degree: 2012, University of Arizona
URL: http://hdl.handle.net/10150/238892
► This thesis explores the role of path integration on the firing of hippocampal place cells and medial entorhinal grid cells. Grid cells fire at equidistant…
(more)
▼ This thesis explores the role of path integration on the firing of hippocampal place cells and medial entorhinal grid cells. Grid cells fire at equidistant locations in an environment, indicating that they keep track of the distance and direction an animal has moved in an environment. One class of model of path integration uses a continuous attractor network to update position information. The first part of this thesis showed that such a network can generate a "look-ahead" of neural activity that sweeps through the positions just visited and about to be visited, on the short time scale that is observedin vivo. Adding intrinsic currents to the neurons in the network model allowed this look-ahead to recur every theta cycle, and generate grid fields of a size comparable to data. Grid cells are a major input the hippocampus, and are hypothesized to be the source of the place specificity of place cells. When an animal explores an open environment, place cells are active in a particular location regardless of the direction in which the animal travels through it. While performing a specific task, such as visiting specific locations in the environment in sequence, however, most place cells are active only in one direction. The second part of this thesis studied the development of this directionality. It was determined that upon the initial appearance of place fields in a novel environment, place cells fired in all directions, supporting the hypothesis that the path integration is the primary determinant of place specificity. The directionality of place fields developed gradually, possibly as a result of learning. Ideas about how this directionality could develop are explored.
Advisors/Committee Members: McNaughton, Bruce L (advisor), Gothard, Katalin (committeemember), Fuglevand, Andrew (committeemember), Zinsmaier, Konrad (committeemember), McNaughton, Bruce L. (committeemember).
Subjects/Keywords: path integration;
spatial navigation;
Neuroscience;
hippocampus;
medial entorhinal cortex
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Navratilova, Z. (2012). The Role of Path Integration on Neural Activity in Hippocampus and Medial Entorhinal Cortex
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/238892
Chicago Manual of Style (16th Edition):
Navratilova, Zaneta. “The Role of Path Integration on Neural Activity in Hippocampus and Medial Entorhinal Cortex
.” 2012. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/238892.
MLA Handbook (7th Edition):
Navratilova, Zaneta. “The Role of Path Integration on Neural Activity in Hippocampus and Medial Entorhinal Cortex
.” 2012. Web. 22 Jan 2021.
Vancouver:
Navratilova Z. The Role of Path Integration on Neural Activity in Hippocampus and Medial Entorhinal Cortex
. [Internet] [Doctoral dissertation]. University of Arizona; 2012. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/238892.
Council of Science Editors:
Navratilova Z. The Role of Path Integration on Neural Activity in Hippocampus and Medial Entorhinal Cortex
. [Doctoral Dissertation]. University of Arizona; 2012. Available from: http://hdl.handle.net/10150/238892

University of Arizona
26.
Greenberg, Paul Arthur.
Functional Stability and Learning in the Dorsolateral Prefrontal Cortex
.
Degree: 2005, University of Arizona
URL: http://hdl.handle.net/10150/195923
► "Stable multi-day recordings from chronically implanted microelectrodes within the dorsolateral prefrontal cortex of two monkeys performing three Go/NoGo visual discrimination tasks (one requiring well-learned responses,…
(more)
▼ "Stable multi-day recordings from chronically implanted microelectrodes within the dorsolateral prefrontal cortex of two monkeys performing three Go/NoGo visual discrimination tasks (one requiring well-learned responses, two requiring learning) demonstrated that the majority of prefrontal neurons were 'functionally stable'. Action potentials of 94 neurons were stable over 2-9 days; 66/94 (70%) of these cells responded each day, 22/94 (23%) never responded significantly, and 6/94 (6%) responded one day but not the next. Of 66 responsive neurons, 55 were selective for either Go or NoGo trials, individual stimuli, or eye movements." (Greenberg and Wilson, 2004) Selectivity was maintained, for 46/55 neurons across all recording days. Response strength (baseline vs. post-stimulation firing rates) and event-related response timing also displayed stability. Stability generalized across neuronal response type suggesting that functional stability is a general property. Long-term recordings from other studies supported similar conclusions suggesting that neurons throughout the brain are functionally stable. Single-day recordings from different neurons within the same cortical regions demonstrated neuronal response flexibility while monkeys learned associations among visual cues, and Go/NoGo behavioral responses. Of 116 neurons, 57 (49%) displayed significant change points in firing rates during novel learning (n=18), reversal learning (n=12), or both tasks (n=27). Six of 57(10.5%) neurons had firing rates changes prior to learning and might have been causally related to the monkeys' behavioral changes. However, only 18/152 (12%) of the total number of firing rate changes occurred prior to the monkeys' learning meaning that most appeared to be the consequences of learning rather than the causes.
Advisors/Committee Members: Fuglevand, Andrew (committeemember), McMullen, Nate (committeemember), Jacobs, Jake (committeemember).
Subjects/Keywords: Functional Stability;
Visual Discrimination Learning;
Prefrontal Cortex;
Single Neuron
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Greenberg, P. A. (2005). Functional Stability and Learning in the Dorsolateral Prefrontal Cortex
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/195923
Chicago Manual of Style (16th Edition):
Greenberg, Paul Arthur. “Functional Stability and Learning in the Dorsolateral Prefrontal Cortex
.” 2005. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/195923.
MLA Handbook (7th Edition):
Greenberg, Paul Arthur. “Functional Stability and Learning in the Dorsolateral Prefrontal Cortex
.” 2005. Web. 22 Jan 2021.
Vancouver:
Greenberg PA. Functional Stability and Learning in the Dorsolateral Prefrontal Cortex
. [Internet] [Doctoral dissertation]. University of Arizona; 2005. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/195923.
Council of Science Editors:
Greenberg PA. Functional Stability and Learning in the Dorsolateral Prefrontal Cortex
. [Doctoral Dissertation]. University of Arizona; 2005. Available from: http://hdl.handle.net/10150/195923

University of Arizona
27.
Johnson, Lise.
DECODING ELECTRIC FIELDS OF THE NERVOUS SYSTEM: INVESTIGATIONS OF INFORMATION STORAGE AND TRANSFER IN THE CENTRAL AND PERIPHERAL NERVOUS SYSTEM
.
Degree: 2010, University of Arizona
URL: http://hdl.handle.net/10150/193574
► Electrical potentials are the fundamental currency of communication in the nervous system. The advanced executive functions of the prefrontal cortex and the motor commands delivered…
(more)
▼ Electrical potentials are the fundamental currency of communication in the nervous system. The advanced executive functions of the prefrontal cortex and the motor commands delivered to the neuromuscular junction, though involved with very different aspects of behavior, both rely on time-varying electrical signals. It is possible to "listen to" the internal communications of the nervous system by measuring the electrical potentials in the extra-cellular space. However, this is only meaningful if there is some way to interpret these signals, which are incredibly complicated and information rich. This dissertation represents an attempt to decode some of these signals in order to reveal their significance for behavior and function. The first study is an investigation of the relationship between different elements of the local field potential in the prefrontal cortex and memory consolidation. It is shown that certain electrographic signatures of non-rapid eye movement sleep, namely K-complexes and low-voltage spindles, are correlated with neuronal replay of recent experiences. It is also shown that the global fluctuations of activity in the population of cells, known as up/down states, is correlated with neuronal replay. Finally, it is shown that high-voltage spindles are not correlated with memory replay, and are therefore functionally different from low-voltage spindles. The second study focuses on the relationship between movements of the upper limb and the coordinated neural control, as measured by the electromyogram (EMG), of the muscles generating that movement. We show that different probability-based models can be used to predict what the pattern of EMG in the different muscles will be for any given kinematic state of the hand. In the third study it is demonstrated that the kinematic output associated with a particular pattern of EMG can be reproduced with electrical stimulation. Thus, it is not only possible to understand the commands issued by the nervous system, it is also possible to issue commands by interfacing with the nervous system directly. Finally, the design for an experiment that would combine EMG prediction with translation of EMG into electrical stimulus patterns is presented. The objective of this study would be to use these methods to fully control the upper limb in a way that would be useful for a functional electrical stimulation-based neuroprosthetic for spinal cord injured patients.
Advisors/Committee Members: Fuglevand, Andrew J (advisor), Fuglevand, Andrew J. (committeemember), Fellous, Jean-Marc (committeemember), Gothard, Katalin M. (committeemember), Koshland, Gail F. (committeemember), Trouard, Theodore P. (committeemember).
Subjects/Keywords: Functional Electrical Stimulation;
Motor Control;
Neuroprosthetics
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Johnson, L. (2010). DECODING ELECTRIC FIELDS OF THE NERVOUS SYSTEM: INVESTIGATIONS OF INFORMATION STORAGE AND TRANSFER IN THE CENTRAL AND PERIPHERAL NERVOUS SYSTEM
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/193574
Chicago Manual of Style (16th Edition):
Johnson, Lise. “DECODING ELECTRIC FIELDS OF THE NERVOUS SYSTEM: INVESTIGATIONS OF INFORMATION STORAGE AND TRANSFER IN THE CENTRAL AND PERIPHERAL NERVOUS SYSTEM
.” 2010. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/193574.
MLA Handbook (7th Edition):
Johnson, Lise. “DECODING ELECTRIC FIELDS OF THE NERVOUS SYSTEM: INVESTIGATIONS OF INFORMATION STORAGE AND TRANSFER IN THE CENTRAL AND PERIPHERAL NERVOUS SYSTEM
.” 2010. Web. 22 Jan 2021.
Vancouver:
Johnson L. DECODING ELECTRIC FIELDS OF THE NERVOUS SYSTEM: INVESTIGATIONS OF INFORMATION STORAGE AND TRANSFER IN THE CENTRAL AND PERIPHERAL NERVOUS SYSTEM
. [Internet] [Doctoral dissertation]. University of Arizona; 2010. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/193574.
Council of Science Editors:
Johnson L. DECODING ELECTRIC FIELDS OF THE NERVOUS SYSTEM: INVESTIGATIONS OF INFORMATION STORAGE AND TRANSFER IN THE CENTRAL AND PERIPHERAL NERVOUS SYSTEM
. [Doctoral Dissertation]. University of Arizona; 2010. Available from: http://hdl.handle.net/10150/193574

University of Arizona
28.
McKiernan, Erin Christy.
The role of specific voltage-activated and calcium-activated potassium currents in shaping motor neuron firing output during rhythmic motor activity
.
Degree: 2010, University of Arizona
URL: http://hdl.handle.net/10150/145732
► Rhythmic muscle contractions underlie a number of behaviors, such as respiration, ingestion, and locomotion, which are necessary for survival. Though in many cases motor neurons…
(more)
▼ Rhythmic muscle contractions underlie a number of behaviors, such as respiration, ingestion, and locomotion, which are necessary for survival. Though in many cases motor neurons (MNs) themselves do not generate the basic motor rhythm, research suggests that the intrinsic properties of MNs may shape the timing of the final motor output. In particular, potassium (K⁺) currents can affect MN excitability and firing in a number of ways, including action potential repolarization, firing frequency, dendritic integration, repetitive firing, and burst termination. The roles played by K⁺ currents, therefore, make them ideal candidates to shape MN firing output during rhythmic activity. Just how crucial MN K⁺ currents are in shaping rhythmic motor output, which currents are crucial and what genes are responsible, and how these currents affect MN firing are areas of active investigation. Unfortunately, many previous studies attempting to answer such questions have relied on manipulations that affect large, and often unidentified, populations of neurons simultaneously. To effectively determine the role of MN currents in shaping rhythmic motor output we must target manipulations of specific ion channels to MNs. We used the Drosophila larval model system because the genetic tools available allow us to do just that. We targeted manipulations of specific calcium (Ca²⁺)-activated and voltageactivated K⁺ currents to identified populations of MNs. We hypothesized that MNs are not simply followers of network drive, but that MN firing output is further shaped during rhythmic motor activity by these K⁺ currents. Overall, our results show that though aspects of the motor output changed, such as burst duration, the system was remarkably robust in the face of K⁺ channel manipulations. Larvae expressing manipulations of the Ca²⁺-activated K⁺ channel, Slowpoke, and voltage-gated K⁺ channels Shal or eag/Shaker, continued to produce rhythmic motor output. Most manipulations had the strongest effect when expressed in cells other than just MNs, while restricting expression to smaller subsets of cells suggested that many of the effects were not intrinsic to the MNs. Even those manipulations which resulted in the strongest effects only changed burst or cycle durations by a few seconds, and did not affect the incidence or regularity of the rhythm. These results suggest that either these MN K⁺ currents minimally shape rhythmic motor output in this system, or compensation for the loss of K⁺ currents occurred. In sum, this work sheds light on the role of K⁺ currents in MNs during rhythmic activity, and points to a number of future directions examining the role of compensation in maintaining crucial rhythmic motor behaviors.
Advisors/Committee Members: Levine, Richard (advisor), Duch, Carsten (advisor), Fuglevand, Andrew (committeemember), Fellous, Jean-Marc (committeemember).
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
McKiernan, E. C. (2010). The role of specific voltage-activated and calcium-activated potassium currents in shaping motor neuron firing output during rhythmic motor activity
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/145732
Chicago Manual of Style (16th Edition):
McKiernan, Erin Christy. “The role of specific voltage-activated and calcium-activated potassium currents in shaping motor neuron firing output during rhythmic motor activity
.” 2010. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/145732.
MLA Handbook (7th Edition):
McKiernan, Erin Christy. “The role of specific voltage-activated and calcium-activated potassium currents in shaping motor neuron firing output during rhythmic motor activity
.” 2010. Web. 22 Jan 2021.
Vancouver:
McKiernan EC. The role of specific voltage-activated and calcium-activated potassium currents in shaping motor neuron firing output during rhythmic motor activity
. [Internet] [Doctoral dissertation]. University of Arizona; 2010. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/145732.
Council of Science Editors:
McKiernan EC. The role of specific voltage-activated and calcium-activated potassium currents in shaping motor neuron firing output during rhythmic motor activity
. [Doctoral Dissertation]. University of Arizona; 2010. Available from: http://hdl.handle.net/10150/145732

University of Arizona
29.
Herrera-Valdez, Marco Arieli.
Relationship Between Nearly-Coincident Spiking and Common Excitatory Synaptic Input in Motor Neurons
.
Degree: 2008, University of Arizona
URL: http://hdl.handle.net/10150/196051
► The activities of pairs of mammalian motor neurons (MNs) receiving varying degrees of common excitatory synaptic input were simulated to study the relationship between nearly-coincident…
(more)
▼ The activities of pairs of mammalian motor neurons (MNs) receiving varying degrees of common excitatory synaptic input were simulated to study the relationship between nearly-coincident spiking and common excitatory drive. The somatic membrane potential of each MN was modeled using a single compartment model. Each MN was modeled toreceive synaptic contacts from hundreds of pre-synaptic fibers. The percentage of pre-synaptic fibers that diverged to supply both MNs of a pair with common synaptic input could be varied from 0 (no common inputs) to 100% (all common inputs). Spikes trains on separate re-synaptic fibers were independent of one another and were modeled as realizations of renewal processes with mean firing rates (10 - 50Hz) resembling that associated with supra-spinal input. Maximum synaptic conductances and time constants were varied across synapsesto match experimentally observed somatic EPSPs. The number of active pre-synaptic fibers to each MN was adjusted in order that the firingrates of MNs were between 8 and 15 Hz. For each common input condition, 100 s of concurrent spiking activity of the MNs was usedto construct cross-correlation histograms. The sizes of the central peaks in the histograms were quantified using both the k' (Ellaway and Murthy 1985) and CIS (Nordstrom et al. 1992) indices ofsynchrony. Monotonically increasing linear relationships between the proportion of common synaptic input and the magnitude of synchronywere observed for both indices. For example, the model predicted that 10% common input would yield a CIS value of 0.27 whereas 100% commoninput would yield a CIS value of 1.5. These values are within the range of values observed experimentally. These results, therefore,provide a means to translate measures of nearly-coincident spiking into plausible renditions of synaptic connectivity.
Advisors/Committee Members: Fuglevand, Andrew J (advisor), Fellous, Jean-Marc (committeemember), Levine, Richard B. (committeemember).
Subjects/Keywords: coincidence and synchrony;
cortico-spinal;
motor neurons;
single compartment;
spike trains;
synaptic input
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Herrera-Valdez, M. A. (2008). Relationship Between Nearly-Coincident Spiking and Common Excitatory Synaptic Input in Motor Neurons
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/196051
Chicago Manual of Style (16th Edition):
Herrera-Valdez, Marco Arieli. “Relationship Between Nearly-Coincident Spiking and Common Excitatory Synaptic Input in Motor Neurons
.” 2008. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/196051.
MLA Handbook (7th Edition):
Herrera-Valdez, Marco Arieli. “Relationship Between Nearly-Coincident Spiking and Common Excitatory Synaptic Input in Motor Neurons
.” 2008. Web. 22 Jan 2021.
Vancouver:
Herrera-Valdez MA. Relationship Between Nearly-Coincident Spiking and Common Excitatory Synaptic Input in Motor Neurons
. [Internet] [Doctoral dissertation]. University of Arizona; 2008. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/196051.
Council of Science Editors:
Herrera-Valdez MA. Relationship Between Nearly-Coincident Spiking and Common Excitatory Synaptic Input in Motor Neurons
. [Doctoral Dissertation]. University of Arizona; 2008. Available from: http://hdl.handle.net/10150/196051

University of Arizona
30.
Kinnick, Tyson Rand.
Understanding the Function of Bestrophin
.
Degree: 2007, University of Arizona
URL: http://hdl.handle.net/10150/193686
► The purpose of this study was to investigate the function of the protein bestrophin-1 (best-1). Previous studies have suggested that best-1 is either a Ca++-activated…
(more)
▼ The purpose of this study was to investigate the function of the protein bestrophin-1 (best-1). Previous studies have suggested that best-1 is either a Ca++-activated Cl- channel (ClCa) and/or that it is a regulator of Ca++ induced responses in the retinal pigment epithelium (RPE).Experiments were performed on whole monolayers of cultured primary fetal human retinal pigment epithelium (fhRPE). The amount and polarity of the transduced proteins exposed at the cell surface, as assessed by domain selective biotinylation, was not altered by overexpression of best-1 or the best-1 mutants W93C or R218C. Best-1 (Wt) transduction of fhRPE increased baseline short circuit current (Isc) over Controls and best-1 mutant experimental groups during electrophysiology on whole monolayers. Cl-ion substitution in the Wt group caused a reduction in Isc that was reversible upon re-introduction of Cl- to the bathing solution. Cl-ion substitution did not significantly alter Isc in any other experimental group. This data supports a regulatory function for best-1 for Cl- transport across the epithelium.Application of the Ca++-ionophore ionomycin resulted in a biphasic response in Control monolayers, which was reduced in monolayers overexpressing best-1. Following exposure to ionomycin, NFA was used to block ClCa currents. NFA resulted in a decrease in the TEP of Controls and Wt monolayers to approximately half the value observed at the maximal response to ionomycin (Peak 2 or P2). The Isc response of Control and Wt monolayers mimicked the TEP response, resulting in an Isc at the end of exposure to NFA that was the same as the Isc at Peak 1 (P1) of the biphasic response to ionomycin. This suggests that ClCa currents are at most responsible for P2 of the ionomycin response, but this is not exclusive of other channels sensitive to NFA being involved. R218C expressing cells showed little response to Ca++ and NFA, and W93C cells were not responsive.In conclusion, with the cellular expression and polarity of best-1 and best-1 mutants the same, the data from the present study support a Ca++ regulatory role for best-1 that functions to prime the RPE to respond to changes in intracellular Ca++.
Advisors/Committee Members: Marmorstein, Alan D (advisor), Fuglevand, Andrew J. (committeemember), Levine, Richard B. (committeemember), McKay, Brian S. (committeemember).
Subjects/Keywords: Physiological Sciences
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APA (6th Edition):
Kinnick, T. R. (2007). Understanding the Function of Bestrophin
. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/193686
Chicago Manual of Style (16th Edition):
Kinnick, Tyson Rand. “Understanding the Function of Bestrophin
.” 2007. Doctoral Dissertation, University of Arizona. Accessed January 22, 2021.
http://hdl.handle.net/10150/193686.
MLA Handbook (7th Edition):
Kinnick, Tyson Rand. “Understanding the Function of Bestrophin
.” 2007. Web. 22 Jan 2021.
Vancouver:
Kinnick TR. Understanding the Function of Bestrophin
. [Internet] [Doctoral dissertation]. University of Arizona; 2007. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10150/193686.
Council of Science Editors:
Kinnick TR. Understanding the Function of Bestrophin
. [Doctoral Dissertation]. University of Arizona; 2007. Available from: http://hdl.handle.net/10150/193686
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