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1.
Gill, Jay Lathen.
A Novel, Context Dependent Two Alternative Forced Choice
Task for the Exploration of the Neural Correlates of Higher Order
Cognition in Mice.
Degree: Department of Molecular Pharmacology, Physiology and
Biotechnology, 2017, Brown University
URL: https://repository.library.brown.edu/studio/item/bdr:733338/ 
► The brain’s ability to attribute valence to sensory stimuli in our environment and modulate these associations to reflect its current state is essential for goal…
(more)
▼ The brain’s ability to attribute valence to sensory
stimuli in our environment and modulate these associations to
reflect its current state is essential for goal directed behavior.
Though several investigations demonstrate the ability of prefrontal
and parietal cortices to carry out these computations, how and
where the external world becomes integrated with internal factors
including context, past experience, and goals remains unknown.
Recent engineering innovations including optogenetics, 2 photo
microscopy coupled with GCaMP, and high channel extracellular
electrode recordings are powerful tools that could be used to
understand the brain’s stages of information processing. However,
their ability to extract signals underlying higher order cognition
is limited by the learning capacity of their optimal system (mice).
For my Master’s Thesis, I have created a novel version of a Two
Alternative Forced Choice Task that entrains context dependent
behavior in mice that is compatible with the aforementioned
techniques.
Advisors/Committee Members: Moore, Christopher (Advisor), Frank, Michael (Reader), Bath, Kevin (Reader).
Subjects/Keywords: behavioral neuroscience
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APA (6th Edition):
Gill, J. L. (2017). A Novel, Context Dependent Two Alternative Forced Choice
Task for the Exploration of the Neural Correlates of Higher Order
Cognition in Mice. (Thesis). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:733338/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Gill, Jay Lathen. “A Novel, Context Dependent Two Alternative Forced Choice
Task for the Exploration of the Neural Correlates of Higher Order
Cognition in Mice.” 2017. Thesis, Brown University. Accessed January 21, 2021.
https://repository.library.brown.edu/studio/item/bdr:733338/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Gill, Jay Lathen. “A Novel, Context Dependent Two Alternative Forced Choice
Task for the Exploration of the Neural Correlates of Higher Order
Cognition in Mice.” 2017. Web. 21 Jan 2021.
Vancouver:
Gill JL. A Novel, Context Dependent Two Alternative Forced Choice
Task for the Exploration of the Neural Correlates of Higher Order
Cognition in Mice. [Internet] [Thesis]. Brown University; 2017. [cited 2021 Jan 21].
Available from: https://repository.library.brown.edu/studio/item/bdr:733338/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Gill JL. A Novel, Context Dependent Two Alternative Forced Choice
Task for the Exploration of the Neural Correlates of Higher Order
Cognition in Mice. [Thesis]. Brown University; 2017. Available from: https://repository.library.brown.edu/studio/item/bdr:733338/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
2.
Tam, Kelly.
Direct vs. indirect pathway optogenetic stimulation during
conditional olfactory learning in mice.
Degree: Department of Molecular Pharmacology, Physiology and
Biotechnology, 2017, Brown University
URL: https://repository.library.brown.edu/studio/item/bdr:733532/
► The basal ganglia has been implicated in motivational behavior, reinforcement learning, reward seeking, and action selection. The dual nature of these behaviors, i.e. encouragement vs.…
(more)
▼ The basal ganglia has been implicated in motivational
behavior, reinforcement learning, reward seeking, and action
selection. The dual nature of these behaviors, i.e. encouragement
vs. discouragement (motivation), reward vs. punishment
(reinforcement learning, reward seeking), go vs. no-go (action
selection), has been hypothesized to be represented by two
anatomically distinct pathways within the basal ganglia circuit,
namely the D1 direct (striatonigral) and the D2 indirect
(striatopallidal) pathways, respectively. While there have been a
variety of behavioral studies supporting this hypothesis, it is
still not known what specific signals are carried by each pathway.
To address this issue, we studied the effects of optogenetic
excitation of direct or indirect pathway during two behavioral
paradigms in mice, i.e. during open-field exploration and an
odor-based Go/No-Go task. For excitation of direct and indirect
pathways, we injected the virus AAV5-EF1a-DIO- hChR2(H134R)-EYFP
into dorsomedial striatum bilaterally in D1-Cre and A2a-Cre mice,
respectively. About 3 weeks after injections two optical fibers
were implanted at the injected regions. In the open-field
exploration task, mice were left in a rectangular chamber to move
freely. Optogenetic stimulation was applied only when the mouse
entered a predetermined region of the chamber. Our results showed
that D1 mice preferred to spend more time on the stimulated region
whereas D2 mice on the non-stimulated. These results are consistent
with previously published work and confirm the basic functionality
of our optogenetic model. Using our verified model, we then
examined the effects of optogenetic stimulation of direct and
indirect pathways on learning by way of the Go/No-Go task, i.e. the
speed of learning, the success rate after learning, and the
reaction times. We trained mice to identify four odors delivered
through an odor port. Two of the odors were used to instruct reward
delivery through a water port (Go trial) and the remaining two to
wait and not go to the water port (No-Go trial). One of each Go and
No-Go odors were primed with optogenetic stimulation during
feedback and reward period. Our data showed that neither the speed
of learning, nor final task performance (>75% success rate) was
significantly altered by optogenetic stimulation in D1 or D2 mice.
However, we observed that the latency in initiating the subsequent
trial was increased with stimulation of the indirect pathway.
Overall, the odor-based Go/No-Go task results do not support the
D1/D2 pathway's involvement in reward/punishment or go/no-go
signals. However, the open field results are still in accord with a
motivation-based signaling.
Advisors/Committee Members: Asaad, Wael (Advisor), Bath, Kevin (Reader), Frank, Michael (Reader).
Subjects/Keywords: motivation learning
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APA (6th Edition):
Tam, K. (2017). Direct vs. indirect pathway optogenetic stimulation during
conditional olfactory learning in mice. (Thesis). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:733532/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Tam, Kelly. “Direct vs. indirect pathway optogenetic stimulation during
conditional olfactory learning in mice.” 2017. Thesis, Brown University. Accessed January 21, 2021.
https://repository.library.brown.edu/studio/item/bdr:733532/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Tam, Kelly. “Direct vs. indirect pathway optogenetic stimulation during
conditional olfactory learning in mice.” 2017. Web. 21 Jan 2021.
Vancouver:
Tam K. Direct vs. indirect pathway optogenetic stimulation during
conditional olfactory learning in mice. [Internet] [Thesis]. Brown University; 2017. [cited 2021 Jan 21].
Available from: https://repository.library.brown.edu/studio/item/bdr:733532/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Tam K. Direct vs. indirect pathway optogenetic stimulation during
conditional olfactory learning in mice. [Thesis]. Brown University; 2017. Available from: https://repository.library.brown.edu/studio/item/bdr:733532/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
3.
Franklin, Nicholas Thompson.
Compositionality in Human Structure Learning.
Degree: Department of Cognitive, Linguistic, and Psychological
Sciences, 2018, Brown University
URL: https://repository.library.brown.edu/studio/item/bdr:792603/
► Humans are remarkably adept at generalizing knowledge between experiences in a way that can be difficult for computers. Often, this entails generalizing constituent pieces of…
(more)
▼ Humans are remarkably adept at generalizing knowledge
between experiences in a way that can be difficult for computers.
Often, this entails generalizing constituent pieces of experiences
that do not fully overlap, but nonetheless share useful
similarities with previously acquired knowledge. A young musician
may learn to play several instruments in different contexts, for
example, learning the flute to play classical and the saxophone to
play jazz. Because the fingerings of the saxophone and the flute
are nearly the same, a musician can re-use previously learned hand
motions for different effect across the two instruments.
Conversely, a musician may learn to play a single song across many
instruments that require completely distinct physical motions, but
yet still transfer knowledge between them. This degree of
compositionality is critical for flexible goal-directed behavior
but can be difficult for computational frameworks because they
often assume an underlying structure of the world that is
incompatible with generalization. Here, I propose a novel
computational framework that leverages the compositional structure
in real-world environments by assuming people generalize goals, or
what to do, independently from a word model, or how to do it. I
examine the computational framework normatively and ask when it
makes sense to generalize goals and world models independently or
together. In a series of experiments, I compare human subject
behavior to model predictions, showing that people adapt their
generalization strategy depending on the environment. Together,
these results sug- gest that no one strategy is best across all
environments, and that while it is adaptive to represent a complex
environment in learnable components, people pay attention to the
relationship between components in their environment.
Advisors/Committee Members: Frank, Michael (Advisor), Badre, David (Reader), Littman, Michael (Reader).
Subjects/Keywords: Cognitive science
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to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Franklin, N. T. (2018). Compositionality in Human Structure Learning. (Thesis). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:792603/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Franklin, Nicholas Thompson. “Compositionality in Human Structure Learning.” 2018. Thesis, Brown University. Accessed January 21, 2021.
https://repository.library.brown.edu/studio/item/bdr:792603/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Franklin, Nicholas Thompson. “Compositionality in Human Structure Learning.” 2018. Web. 21 Jan 2021.
Vancouver:
Franklin NT. Compositionality in Human Structure Learning. [Internet] [Thesis]. Brown University; 2018. [cited 2021 Jan 21].
Available from: https://repository.library.brown.edu/studio/item/bdr:792603/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Franklin NT. Compositionality in Human Structure Learning. [Thesis]. Brown University; 2018. Available from: https://repository.library.brown.edu/studio/item/bdr:792603/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
4.
Fox, Neal P.
Top-Down Effects on Speech Perception: An Integrated
Computational and Behavioral Approach.
Degree: PhD, Cognitive Sciences, 2016, Brown University
URL: https://repository.library.brown.edu/studio/item/bdr:674171/
► During auditory language comprehension, bottom-up acoustic cues in the sensory signal are critical to the recognition of spoken words. However, listeners are also sensitive to…
(more)
▼ During auditory language comprehension, bottom-up
acoustic cues in the sensory signal are critical to the recognition
of spoken words. However, listeners are also sensitive to
higher-level processing; in general, identification of ambiguous
targets is biased by prior expectations (e.g., words over
non-words, contextually consistent words over inconsistent words).
Although it is clear that such top-down cues influence word
recognition, how they do so is less clear. The present work
examines several questions about the computational principles
underlying top-down effects on speech perception, focusing
primarily on the influence of a preceding sentential context (e.g.,
Valerie hated the... vs. Brett hated to...) on the identification
of phonetically ambiguous targets from voice-onset time continua
(e.g., between bay and pay). Chapter 1 considers a longstanding
debate: do top-down effects result from interactive modulation of
perceptual processing or from entirely autonomous, decision-level
processing? Some research has suggested that the time course of
top-down effects is incompatible with interactive models. However,
two experiments illustrate that, with appropriate controls, the
predictions of interactive models are supported. Ultimately,
though, two weaknesses of existing spoken word recognition models
(whether interactive or autonomous) are that they ignore the role
of sentential context and that they ignore the enormous variability
in the size of top-down effects. To address these gaps, Chapter 2
introduces BIASES (short for Bayesian Integration of Acoustic and
Sentential Evidence in Speech), a newly developed computational
model of speech perception. Chapter 3 demonstrates BIASES’ ability
to predict and explain fine-grained variability and asymmetries in
both novel experimental data and in previously published work.
Finally, Chapter 4 employs BIASES to examine top-down processing in
patients with aphasia. Model-based analysis of previously published
data and new data utilizing stimuli from Chapter 1 suggest that
patients experience both bottom-up processing deficits and lexical
processing deficits. Importantly, those impairments differ as a
function of patients’ clinical diagnoses. In sum, this work offers
new insights into the computations occurring at the interface
between the perceptual processing of speech and the cognitive and
linguistic processing of language.
Advisors/Committee Members: Blumstein, Sheila (Director), Frank, Michael (Reader), Morgan, James (Reader).
Subjects/Keywords: computational modeling
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Fox, N. P. (2016). Top-Down Effects on Speech Perception: An Integrated
Computational and Behavioral Approach. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:674171/
Chicago Manual of Style (16th Edition):
Fox, Neal P. “Top-Down Effects on Speech Perception: An Integrated
Computational and Behavioral Approach.” 2016. Doctoral Dissertation, Brown University. Accessed January 21, 2021.
https://repository.library.brown.edu/studio/item/bdr:674171/.
MLA Handbook (7th Edition):
Fox, Neal P. “Top-Down Effects on Speech Perception: An Integrated
Computational and Behavioral Approach.” 2016. Web. 21 Jan 2021.
Vancouver:
Fox NP. Top-Down Effects on Speech Perception: An Integrated
Computational and Behavioral Approach. [Internet] [Doctoral dissertation]. Brown University; 2016. [cited 2021 Jan 21].
Available from: https://repository.library.brown.edu/studio/item/bdr:674171/.
Council of Science Editors:
Fox NP. Top-Down Effects on Speech Perception: An Integrated
Computational and Behavioral Approach. [Doctoral Dissertation]. Brown University; 2016. Available from: https://repository.library.brown.edu/studio/item/bdr:674171/
5.
Doll, Bradley Benjamin.
Corticostriatal substrates of confirmation bias in
reinforcement learning: behavior, genetics, and
neurocomputation.
Degree: PhD, Cognitive Sciences, 2012, Brown University
URL: https://repository.library.brown.edu/studio/item/bdr:297598/
► A wealth of research shows how the dopaminergic frontostriatal system incrementally learns from rewards and punishments. Midbrain dopamine cells show phasic firing rate changes in…
(more)
▼ A wealth of research shows how the dopaminergic
frontostriatal system incrementally learns from
rewards and punishments. Midbrain dopamine cells show phasic
firing rate changes in response to outcomes, projecting “prediction
error” teaching signals to the basal ganglia. These shifts in
dopamine levels mediate synaptic plasticity in the basal ganglia,
which learn over experience to
select rewarding actions, and avoid punishing ones. Though
experience-based learning can
powerfully drive adaptive behavior, humans also learn
indirectly through rules, advice, and
instruction. This thesis explores how explicit information
about reward contingencies influences
experiential learning by building on the large body of
empirical work on the dopamine system,
and mathematical models of the learning mechanism it affords.
Experiments demonstrate that subjects are unduly influenced by
prior instruction in stochastic learning environments, acting
accordance with this information even when experiential evidence
indicates that it is incorrect. Computational models developed to
reproduce this behavior propose that a confirmation bias mechanism
accounts for the disproportionate influence of instruction. In
these models, prefrontal cortical representations of instruction
activate striatal cells involved in instruction-following,
indirectly changing the effects of the dopaminergic teaching
signal, such that the impact of instruction-consistent gains is
increased, and the effect of inconsistent losses is reduced.
Genetic and behavioral experiments show how differences in the
efficacy of either basal ganglia or prefrontal cortex change the
influence of instruction in ways consistent with model predictions.
This thesis contributes to a growing body of research that suggests
the brain’s multiple memory systems are more integrated than
previously thought. Moreover, these data expand the known role of
the dopaminergic frontostriatal system, showing how the
experiential learning mechanism it supports can also explain rich
psychological data.
Advisors/Committee Members: Frank, Michael (Director), Sloman, Steven (Reader), Badre, David (Reader).
Subjects/Keywords: reinfocement learning
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APA (6th Edition):
Doll, B. B. (2012). Corticostriatal substrates of confirmation bias in
reinforcement learning: behavior, genetics, and
neurocomputation. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:297598/
Chicago Manual of Style (16th Edition):
Doll, Bradley Benjamin. “Corticostriatal substrates of confirmation bias in
reinforcement learning: behavior, genetics, and
neurocomputation.” 2012. Doctoral Dissertation, Brown University. Accessed January 21, 2021.
https://repository.library.brown.edu/studio/item/bdr:297598/.
MLA Handbook (7th Edition):
Doll, Bradley Benjamin. “Corticostriatal substrates of confirmation bias in
reinforcement learning: behavior, genetics, and
neurocomputation.” 2012. Web. 21 Jan 2021.
Vancouver:
Doll BB. Corticostriatal substrates of confirmation bias in
reinforcement learning: behavior, genetics, and
neurocomputation. [Internet] [Doctoral dissertation]. Brown University; 2012. [cited 2021 Jan 21].
Available from: https://repository.library.brown.edu/studio/item/bdr:297598/.
Council of Science Editors:
Doll BB. Corticostriatal substrates of confirmation bias in
reinforcement learning: behavior, genetics, and
neurocomputation. [Doctoral Dissertation]. Brown University; 2012. Available from: https://repository.library.brown.edu/studio/item/bdr:297598/
6.
Sofer, Imri.
Setting boundaries in space: A model of rapid visual
categorization of natural images.
Degree: PhD, Cognitive Sciences, 2014, Brown University
URL: https://repository.library.brown.edu/studio/item/bdr:386267/
► In the last couple of decades, categorization experiments using natural images have started to unravel the way our brain represents and categorizes visual information. Unfortunately,…
(more)
▼ In the last couple of decades, categorization
experiments using natural images have started to unravel the way
our brain represents and categorizes visual information.
Unfortunately, natural stimuli lack any clear parameterization, and
therefore many of those experiments are difficult to control,
analyze, and interpret. This led investigators to interpret their
results using abstract and general theories that lack quantitative
predictions. Moreover, these interpretations are sometimes
inconsistent with predictions from perceptual categorization
models, since it is unclear how these models can be applied to
natural stimuli. In this thesis we bridge the gap between
categorization models and natural scenes categorization
experiments, and show that rapid visual categorization results are
a simple outcome of discriminability between two categories.
Towards this, we derive a simple measure of natural scene
discriminability using a decision boundary, learned over a
rudimentary visual representation. We then measure the difficulty
of classifying an individual image, by measuring its distance to
the decision boundary. Empirical distributions of discriminability
values are used to predict human accuracy and reaction times across
tasks and stimuli sets. We then extend the model to predict full
reaction time distributions. Using a combination of simulations and
psychophysics experiments, we validate the model assumptions, show
that it is consistent with a large set of published results, and
predict novel categorization effects. Our work greatly improves on
the current status in several aspects: First, the theory generates
quantitative and testable predictions of human's speed and accuracy
in natural scene categorization tasks, both at the single image
level and the category level; second, it allows to control and
design experiments based on measurable visual information; third,
it provides a simple, elegant, and intuitive interpretation of
novel and existing results based on discriminability between
targets and distractors.
Advisors/Committee Members: Serre, Thomas (Director), Frank, Michael (Reader), Festa, Elena (Reader).
Subjects/Keywords: visual categorization
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APA ·
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MLA ·
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CSE |
Export
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Manager
APA (6th Edition):
Sofer, I. (2014). Setting boundaries in space: A model of rapid visual
categorization of natural images. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:386267/
Chicago Manual of Style (16th Edition):
Sofer, Imri. “Setting boundaries in space: A model of rapid visual
categorization of natural images.” 2014. Doctoral Dissertation, Brown University. Accessed January 21, 2021.
https://repository.library.brown.edu/studio/item/bdr:386267/.
MLA Handbook (7th Edition):
Sofer, Imri. “Setting boundaries in space: A model of rapid visual
categorization of natural images.” 2014. Web. 21 Jan 2021.
Vancouver:
Sofer I. Setting boundaries in space: A model of rapid visual
categorization of natural images. [Internet] [Doctoral dissertation]. Brown University; 2014. [cited 2021 Jan 21].
Available from: https://repository.library.brown.edu/studio/item/bdr:386267/.
Council of Science Editors:
Sofer I. Setting boundaries in space: A model of rapid visual
categorization of natural images. [Doctoral Dissertation]. Brown University; 2014. Available from: https://repository.library.brown.edu/studio/item/bdr:386267/
7.
Rao, Naveen G.
Cortical dynamics of movement planning, execution, and
sensory integration in parietal-motor networks.
Degree: PhD, Neuroscience, 2012, Brown University
URL: https://repository.library.brown.edu/studio/item/bdr:297696/
► In this thesis, we explored mechanisms for how the brain transforms incoming sensory information into meaningful motor output. The motor cortex is known as the…
(more)
▼ In this thesis, we explored mechanisms for how the
brain transforms incoming sensory information into meaningful motor
output. The motor cortex is known as the area of the cortex most
closely associated with movement. In our first result, we showed MI
is more heavily involved in this sensory-to-motor transformation
than previously thought. We showed that MI cells have, not only
movement-related activity, but also responses to visual cues that
are meaningful in the context of current or upcoming movements.
Past studies have indicated that MI is likely not involved in
spatial processing, so we surmise that local ensembles of MI
neurons are capable of associating certain sensory inputs with
motor plans when the sensory information does not require spatial
processing to be relevant to motor output. Next, we showed that
area 2/5 neurons on the surface of the postcentral gyrus tend not
to respond to visual cues and tend to become active after movement
has commenced. Thus, they are unlikely to be involved in the
sensorimotor transformation in our task. We showed that both area
2/5 and MI have robust responses to physical perturbation of the
arm, indicating both areas receive proprioceptive information.
These responses have a similar latency in both areas, suggesting a
parallel computation is occurring in each area. However, area 2/5
responses to perturbation incorporate both the ongoing movement
direction as well as the direction of perturbation, while MI
responses are related only to perturbation direction. Finally, we
presented evidence that the goal information in area 2/5 came from
early MI activity before movements, but does not result in spiking
in area 2/5. Rather, we believe this goal information from MI
influences the area 2/5 network to contextually process incoming
sensory information. Taken together, these results suggest that
area 2/5 processes sensory information in the context of this early
motor plan. This interaction allows spatial corroboration of the
effector limb to goal and possibly spatial motor error
calculation.
Advisors/Committee Members: Donoghue, John (Director), Sheinberg, David (Reader), Frank, Michael (Reader), Kalasha, John (Reader).
Subjects/Keywords: neural coding
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Rao, N. G. (2012). Cortical dynamics of movement planning, execution, and
sensory integration in parietal-motor networks. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:297696/
Chicago Manual of Style (16th Edition):
Rao, Naveen G. “Cortical dynamics of movement planning, execution, and
sensory integration in parietal-motor networks.” 2012. Doctoral Dissertation, Brown University. Accessed January 21, 2021.
https://repository.library.brown.edu/studio/item/bdr:297696/.
MLA Handbook (7th Edition):
Rao, Naveen G. “Cortical dynamics of movement planning, execution, and
sensory integration in parietal-motor networks.” 2012. Web. 21 Jan 2021.
Vancouver:
Rao NG. Cortical dynamics of movement planning, execution, and
sensory integration in parietal-motor networks. [Internet] [Doctoral dissertation]. Brown University; 2012. [cited 2021 Jan 21].
Available from: https://repository.library.brown.edu/studio/item/bdr:297696/.
Council of Science Editors:
Rao NG. Cortical dynamics of movement planning, execution, and
sensory integration in parietal-motor networks. [Doctoral Dissertation]. Brown University; 2012. Available from: https://repository.library.brown.edu/studio/item/bdr:297696/
8.
Wiecki, Thomas V.
Computational Psychiatry: Combining multiple levels of
analysis to understand brain disorders.
Degree: PhD, Psychology, 2014, Brown University
URL: https://repository.library.brown.edu/studio/item/bdr:419389/
► The premise of the emerging field of computational psychiatry is to use models from computational cognitive neuroscience to gain deeper insights into mental illness. In…
(more)
▼ The premise of the emerging field of computational
psychiatry is to use models from computational cognitive
neuroscience to gain deeper insights into mental illness. In this
thesis my goal is to provide an overview of this endeavor and
advance it by developing new software as well as quantitative
methods. To demonstrate their usefulness I will apply these methods
to real-world data sets. A central theme will be the bridging of
multiple levels of analysis of the brain ranging from neuroscience
and cognition to behavior. First, I describe the current crisis in
research and treatment of mental illness and argue that
computational psychiatry provides the tools to solve some
long-standing issues that hindered progress in this area. To
provide a coherent scope, I will focus on response inhibition as it
provides a rich literature in each of the different levels of
analysis with clear links to psychopathology. Next, I first
establish a neuronal basis by presenting a biologically plausible
neural network model of key areas involved in response inhibition.
Capturing the high-level computations of this fairly complex model
requires more abstract cognitive process models. Towards this goal
we developed software to estimate a decision making model in a
hierarchical Bayesian manner which improves parameter recovery in a
simulation study. I then bridge the neuronal and cognitive level by
fitting a psychological process model to the simulated behavioral
output of the neural network model under certain biological
anipulations. By analyzing which biological manipulation is best
captured by changes in certain high-level computational parameters
I start to link both levels of analysis. I then apply this same
psychological process model to two data sets from selective
response inhibition tasks administered to patients suffering from
Huntington's disease and depression. Having identified
neurobiological correlates of certain model parameters allows to
then formulate theories not only about cognitive processes impacted
by these disorders but also which neuronal mechanism are likely to
be involved.
Advisors/Committee Members: Frank, Michael (Director), Serre, Thomas (Reader), Sudderth, Erik (Reader), Greenberg, Benjamin (Reader).
Subjects/Keywords: computational psychiatry
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APA (6th Edition):
Wiecki, T. V. (2014). Computational Psychiatry: Combining multiple levels of
analysis to understand brain disorders. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:419389/
Chicago Manual of Style (16th Edition):
Wiecki, Thomas V. “Computational Psychiatry: Combining multiple levels of
analysis to understand brain disorders.” 2014. Doctoral Dissertation, Brown University. Accessed January 21, 2021.
https://repository.library.brown.edu/studio/item/bdr:419389/.
MLA Handbook (7th Edition):
Wiecki, Thomas V. “Computational Psychiatry: Combining multiple levels of
analysis to understand brain disorders.” 2014. Web. 21 Jan 2021.
Vancouver:
Wiecki TV. Computational Psychiatry: Combining multiple levels of
analysis to understand brain disorders. [Internet] [Doctoral dissertation]. Brown University; 2014. [cited 2021 Jan 21].
Available from: https://repository.library.brown.edu/studio/item/bdr:419389/.
Council of Science Editors:
Wiecki TV. Computational Psychiatry: Combining multiple levels of
analysis to understand brain disorders. [Doctoral Dissertation]. Brown University; 2014. Available from: https://repository.library.brown.edu/studio/item/bdr:419389/
9.
He, Mingjian.
Aging Effects on Task-Evoked Pupillary Responses.
Degree: Department of Cognitive, Linguistic, and Psychological
Sciences, 2018, Brown University
URL: https://repository.library.brown.edu/studio/item/bdr:792761/
► Abstract of Aging Effects on Task-Evoked Pupillary Reponses, by Mingjian He, Degree ScM., Brown University, May 2018. Previous studies have found decreased cell counts and…
(more)
▼ Abstract of Aging Effects on Task-Evoked Pupillary
Reponses, by Mingjian He, Degree ScM.,
Brown University, May 2018.
Previous studies have found decreased cell counts and increased
neurofibrillary pathology in locus-coeruleus (LC) nuclei in the
aging population, and impairments of the noradrenergic (NA)
neuromodulatory system have been hypothesized to mediate
age-related cognitive decline. This study utilized task-evoked
pupil dilation to investigate age-related changes in the functional
integrity of the LC-NA system during active task performance. To
capture the broad influence of NA neuromodulation on cognitive
processes, three cognitive tasks were administered incorporating
eye-tracking measurements to examine the roles of LC-NA signaling
in: 1) arousal response using a phasic alerting task; 2) memory
retrieval using a recognition memory task; and 3) conflict
resolution using a flanker task. Using a novel multiple regression
approach to pupillary data, phasic pupillary responses to task
manipulations were characterized as continuous response curves
across the test trial duration. Results from healthy young adults
replicated the patterns of increased pupil dilation previously
reported in pupillometry studies of the three cognitive tasks.
Despite general slowing and reduced memory performance, the healthy
elderly participants nonetheless showed task-evoked pupillary
responses comparable to young adults in the phasic alerting and
recognition memory tasks. However, associations between pupil
dilation and behavioral performance were found to be attenuated
with aging in these two tasks. In the flanker task, a pupillary
response to congruency conditions was observed only in the young
adults but not in the elderly participants, possibly due to a
strategic shift in coping with potential response conflicts in the
elderly group. Overall, the patterns of pupillary responses
characterized in this study suggest: 1) preserved functional
properties of the LC-NA system during cognitive task performance in
aging; and 2) reduced neuromodulatory efficacy of NA projections on
downstream sensory-motor processes. Taken together, results from
this study demonstrated an improved analytical approach to
pupillometry data for assessing functional LC-NA activity, and
identified intact phasic responses of the LC-NA system in healthy
aging that, unlike young adults, were decoupled from observed
behavioral performance.
Advisors/Committee Members: Heindel, William (Advisor), Frank, Michael (Reader), Badre, David (Reader), Festa, Elena (Reader).
Subjects/Keywords: cognitive functioning
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
He, M. (2018). Aging Effects on Task-Evoked Pupillary Responses. (Thesis). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:792761/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
He, Mingjian. “Aging Effects on Task-Evoked Pupillary Responses.” 2018. Thesis, Brown University. Accessed January 21, 2021.
https://repository.library.brown.edu/studio/item/bdr:792761/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
He, Mingjian. “Aging Effects on Task-Evoked Pupillary Responses.” 2018. Web. 21 Jan 2021.
Vancouver:
He M. Aging Effects on Task-Evoked Pupillary Responses. [Internet] [Thesis]. Brown University; 2018. [cited 2021 Jan 21].
Available from: https://repository.library.brown.edu/studio/item/bdr:792761/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
He M. Aging Effects on Task-Evoked Pupillary Responses. [Thesis]. Brown University; 2018. Available from: https://repository.library.brown.edu/studio/item/bdr:792761/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
10.
Cockburn, Jeffrey A.P.
What you should do (and what you really do) when you don’t
know what to do: Information seeking during value based decision
making.
Degree: PhD, Cognitive Sciences, 2015, Brown University
URL: https://repository.library.brown.edu/studio/item/bdr:419466/
► Learning and action selection have been well studied within the confines of a stable environment. These efforts have led to significant advances in our understanding…
(more)
▼ Learning and action selection have been well studied
within the confines of a stable environment. These efforts have led
to significant advances in our understanding of these processes
from behavioural, cognitive and neuroscientific perspectives. Yet,
the world is volatile, and we have only recently begun to probe how
instability influences learning and action selection processes.
Here, I outline an examination of theoretical and empirical
findings related to learning and action selection in volatile
settings, focusing primarily on the role of uncertainty; that is,
when the state of the environment is not fully known. I propose a
heuristic approximation of the optimal solution to action selection
in a volatile environment, where expected reward and expected
uncertainty reduction blend to shape action utility. Here, three
experiments probing human strategies of coping with uncertainty are
compared to model-based predictions, revealing human response
patterns are better predicted by the heuristic model than the
optimal solution. Finally, ongoing scalp electroencephalography
(EEG) was analyzed to reveal separable signals associated with
action utility and uncertainty reduction. Together, the results
discussed here suggest that the brain may deploy a computationally
attractive heuristic strategy that blends reward and information
gain when coping with action selection during periods of
uncertainty.
Advisors/Committee Members: Frank, Michael (Director), Badre, David (Reader), Littman, Michael (Reader), Cushman, Fiery (Reader).
Subjects/Keywords: latent structure
Record Details
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Record Details
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Cockburn, J. A. P. (2015). What you should do (and what you really do) when you don’t
know what to do: Information seeking during value based decision
making. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:419466/
Chicago Manual of Style (16th Edition):
Cockburn, Jeffrey A P. “What you should do (and what you really do) when you don’t
know what to do: Information seeking during value based decision
making.” 2015. Doctoral Dissertation, Brown University. Accessed January 21, 2021.
https://repository.library.brown.edu/studio/item/bdr:419466/.
MLA Handbook (7th Edition):
Cockburn, Jeffrey A P. “What you should do (and what you really do) when you don’t
know what to do: Information seeking during value based decision
making.” 2015. Web. 21 Jan 2021.
Vancouver:
Cockburn JAP. What you should do (and what you really do) when you don’t
know what to do: Information seeking during value based decision
making. [Internet] [Doctoral dissertation]. Brown University; 2015. [cited 2021 Jan 21].
Available from: https://repository.library.brown.edu/studio/item/bdr:419466/.
Council of Science Editors:
Cockburn JAP. What you should do (and what you really do) when you don’t
know what to do: Information seeking during value based decision
making. [Doctoral Dissertation]. Brown University; 2015. Available from: https://repository.library.brown.edu/studio/item/bdr:419466/
. 
Open Access Theses and Dissertations