Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for +publisher:"EPFL" +contributor:("Hill, Sean"). Showing records 1 – 2 of 2 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


EPFL

1. Reimann, Michael. The In-Silico Neocortical Microcircuit: From Structure to Dynamics.

Degree: 2014, EPFL

The neocortex is one of the most important brain regions, occupying more than 80% of the brain volume in mammals and contributing massively to its capability of perceiving and interpreting then environment. While it has been extensively studied, it is still largely unclear how it accomplishes the enormous computational tasks it is faced with. A number of structural features are conserved across the cortex, such as its vertical organization in six individual layers with a large number of morphologically unique neuron types. The exceptional horizontal uniformity, lead to the hypothesis of horizontally repeated unitary microcircuits, the idea that the cortex consists of a number of relatively uniform horizontally repeated modules, each with their own function in the concert of neural activity. While a rough mapping of function to cortical region is virtually identical between individuals and very similar between species, the extraordinary plasticity of the cortex allows functions of damaged parts to be taken over by neighboring regions. This indicates that flexible, "reprogrammable" modules implement the functions of the cortex. The Blue Brain Project (BBP) aims to build a facility for the collection and integration of available data on the fundamental structure and operating principles of the cortex to build and continuously refine a detailed, bottom-up model of the unitary microcircuit. It can then be used as a building block for the construction and simulation of larger cortical regions. A bottom-upmodel such as the one of the BBP aims to match the object being represented primarily on an underlying physical level. As such it is guaranteed to be anchored in real world physical constraints, this however comes with the disadvantage that on a higher level the behavior of the model is undetermined. The goal of this thesis is to study and characterize the model to learnmore about its function and what determines it. In order to ensure the biological relevance, this endeavour was to be tightly linked with comparisons to and validations against relevant experimental data. I concluded that the simulation of extracellular electrical signals are the right tool to link characterization and validation, due to their great importance in in-vitro work. I authored several improvements to the model to ensure the biological accuracy of the computed extracellular signals, the most important being the derivation of the local connectome inside the modeled microcircuit. Next, I implemented software for the calculation of extracellular signals during the course of a simulation on a BlueGene/P supercomputer. The method for the calculation is flexible and can discern between the contributions of individual cells. In addition to validating the signal against in-vitro data, this allowed us to analyze the composition of the signals in a way that is impossible outside of a simulation. The method revealed the crucial role of active currents in the local field potential, i.e. the relatively slow deflections in extracellular signals. We also… Advisors/Committee Members: Markram, Henry, Hill, Sean.

Subjects/Keywords: neocortical microcircuit; in-silico; connectome; synaptic pathways; plasticity; cable-theory; extracellular potential; local field potential; frequency scaling; synaptic currents; action potential

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Reimann, M. (2014). The In-Silico Neocortical Microcircuit: From Structure to Dynamics. (Thesis). EPFL. Retrieved from http://infoscience.epfl.ch/record/198684

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):

Reimann, Michael. “The In-Silico Neocortical Microcircuit: From Structure to Dynamics.” 2014. Thesis, EPFL. Accessed June 25, 2019. http://infoscience.epfl.ch/record/198684.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Reimann, Michael. “The In-Silico Neocortical Microcircuit: From Structure to Dynamics.” 2014. Web. 25 Jun 2019.

Vancouver:

Reimann M. The In-Silico Neocortical Microcircuit: From Structure to Dynamics. [Internet] [Thesis]. EPFL; 2014. [cited 2019 Jun 25]. Available from: http://infoscience.epfl.ch/record/198684.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Reimann M. The In-Silico Neocortical Microcircuit: From Structure to Dynamics. [Thesis]. EPFL; 2014. Available from: http://infoscience.epfl.ch/record/198684

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


EPFL

2. Ramaswamy, Srikanth. Emergent Properties of in silico Synaptic Transmission in a Model of the Rat Neocortical Column.

Degree: 2011, EPFL

The cerebral cortex occupies nearly 80% of the entire volume of the mammalian brain and is thought to subserve higher cognitive functions like memory, attention and sensory perception. The neocortex is the newest part in the evolution of the cerebral cortex and is perhaps the most intricate brain region ever studied. The neocortical microcircuit is the smallest Œecosystem‚ of the neocortex that consists of a rich assortment of neurons, which are diverse in both their morphological and electrical properties. In the neocortical microcircuit, neurons are horizontally arranged in 6 distinct sheets called layers. The fundamental operating unit of the neocortical microcircuit is believed to be the Neocortical Column (NCC). Functionally, a single NCC is an arrangement of thousands of neurons in a vertical fashion spanning across all the 6 layers. The structure of the entire neocortex arises from a repeated and stereotypical arrangement of several thousands of such columns, where neurons transmit information to each other through specialized points of information transfer called synapses. The dynamics of synaptic transmission can be as diverse as the neurons defining a connection and are crucial to foster the functional properties of the neocortical microcircuit. The Blue Brain Project (BBP) is the first comprehensive endeavour to build a unifying model of the NCC by systematic data integration and biologically detailed simulations. Through the past 5 years, the BBP has built a facility for a data-constraint driven approach towards modelling and integrating biological information across multiple levels of complexity. Guided by fundamental principles derived from biological experiments, the BBP simulation toolchain has undergone a process of continuous refinement to facilitate the frequent construction of detailed in silico models of the NCC. The focus of this thesis lies in characterizing the functional properties of in silico synaptic transmission by incorporating principles of synaptic communication derived through biological experiments. In order to study in silico synaptic transmission it is crucial to gain an understanding of the key players influencing the manner in which synaptic signals are processed in the neocortical microcircuit - ion channel kinetics and distribution profiles, single neuron models and dynamics of synaptic pathways. First, by means of exhaustive literature survey, I identified ion channel kinetics and their distribution profiles on neocortical neurons to build in silico ion channel models. Thereafter, I developed a prototype framework to analyze the somatic and dendritic features of single neuron models constrained by ion channel kinetics. Finally, within a simulation framework integrating the ion channels, single… Advisors/Committee Members: Markram, Henry, Hill, Sean Lewis.

Subjects/Keywords: neocortical column; in silico; in vitro; calibration; validation; ion channel models; single neuron models; synaptic transmission; probabilistic synapse model; synaptic pathways; excitatory and inhibitory connections; colonne néocorticale; in silico; in vitro; calibration; validation; modèles de canaux ioniques; modèles de neurones individuels; modèle synaptique probabiliste; voies synaptiques; connexions excitatrices et inhibitrices

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Ramaswamy, S. (2011). Emergent Properties of in silico Synaptic Transmission in a Model of the Rat Neocortical Column. (Thesis). EPFL. Retrieved from http://infoscience.epfl.ch/record/168660

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):

Ramaswamy, Srikanth. “Emergent Properties of in silico Synaptic Transmission in a Model of the Rat Neocortical Column.” 2011. Thesis, EPFL. Accessed June 25, 2019. http://infoscience.epfl.ch/record/168660.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Ramaswamy, Srikanth. “Emergent Properties of in silico Synaptic Transmission in a Model of the Rat Neocortical Column.” 2011. Web. 25 Jun 2019.

Vancouver:

Ramaswamy S. Emergent Properties of in silico Synaptic Transmission in a Model of the Rat Neocortical Column. [Internet] [Thesis]. EPFL; 2011. [cited 2019 Jun 25]. Available from: http://infoscience.epfl.ch/record/168660.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Ramaswamy S. Emergent Properties of in silico Synaptic Transmission in a Model of the Rat Neocortical Column. [Thesis]. EPFL; 2011. Available from: http://infoscience.epfl.ch/record/168660

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.