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Neural Field Theory and Brain Connectivity
Title
Neural Field Theory and Brain Connectivity.
Creator
Tayefeh, Vahid, Fuchs, Armin, Graduate College
Abstract/Description
Spatially continuous cortical surface is composed of neural ensembles interconnected with a general connectivity embedded local homogeneous connectivity to nearest neighbors and global heterogeneous projections to distant areas. Interconnection delay and long-range connectivity in neural field models shows activity transfer via neural oscillation. Destabilization mechanism of two-point connected dynamical neural system with spatially variant connection topology as a control parameter leads to...
Show moreSpatially continuous cortical surface is composed of neural ensembles interconnected with a general connectivity embedded local homogeneous connectivity to nearest neighbors and global heterogeneous projections to distant areas. Interconnection delay and long-range connectivity in neural field models shows activity transfer via neural oscillation. Destabilization mechanism of two-point connected dynamical neural system with spatially variant connection topology as a control parameter leads to phase transition and macroscopic coherent spatiotemporal pattern formation of neural activity. Authors are intended to generalize this neural field dynamic to more realistic geometries such as a sphere.
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Date Issued
2014
PURL
http://purl.flvc.org/fau/fd/FA00005856
Format
Document (PDF)
Neural field dynamics on a spherical cortical surface with long-range connectivity and finite propagation speed
Title
Neural field dynamics on a spherical cortical surface with long-range connectivity and finite propagation speed.
Creator
Tayefeh, Vahid, Fuchs, Armin, Graduate College
Abstract/Description
The neuronal ensembles in cortical tissue, which tend to behave as single functional units, communicate with each other and process information over time. Neural activity fields, in form of spatially continuous networks, can be used to model a variety of neurobiological phenomena. The connection topology of brain tissue is such that a cortical area is not only connected to its neighbors locally, but also has global projection to distant areas via a fiber system. Such projections not only...
Show moreThe neuronal ensembles in cortical tissue, which tend to behave as single functional units, communicate with each other and process information over time. Neural activity fields, in form of spatially continuous networks, can be used to model a variety of neurobiological phenomena. The connection topology of brain tissue is such that a cortical area is not only connected to its neighbors locally, but also has global projection to distant areas via a fiber system. Such projections not only serve to organize local dynamics within cortical areas but timing of these processes at different sites will affect the overall emerging pattern and contributes to the macroscopic organization and global dynamics of neural activity. The dynamics of this neural field activity gives rise to pattern formation phenomena and self-organization. Our macroscopic spatiotemporal pattern formation approach assumes the existence of an order parameter dynamics and leads to phenomenological models to understand the collective phenomena even though the microscopic dynamics is not completely known. We are investigating how the emerging patterns depend on the space-time structure of the coupling between functional units i.e. long-range heterogeneous pathways coupling strength (space) and the axonal time delay due to propagation with finite speed between areas (time). We analyze the stability of the rest-state activity of a neural field as manipulating heterogeneous two-point connections varies network connection topology in two geometries with periodic boundary conditions: a closed one-dimensional loop and a closed spherical 2- D cortical surface.
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Date Issued
2015
PURL
http://purl.flvc.org/fau/fd/FA00005914
Format
Document (PDF)
White matter networks indicative of Alzheimer's disease from diffusion MRI
Title
White matter networks indicative of Alzheimer's disease from diffusion MRI.
Creator
Hahn, William E., Fuchs, Armin, Graduate College
Date Issued
2013-04-12
PURL
http://purl.flvc.org/fcla/dt/3361307
Subject Headings
Alzheimer's disease, Diffusion tensor imaging, Diffusion magnetic resonance imaging
Format
Document (PDF)
Beyond the blank slate: routes to learning new coordination patterns depend on the intrinsic dynamics of the learner—experimental evidence and theoretical model
Title
Beyond the blank slate: routes to learning new coordination patterns depend on the intrinsic dynamics of the learner—experimental evidence and theoretical model.
Creator
Kostrubiec, Viviane, Zanone, Pier-Giorgio, Fuchs, Armin, Kelso, J. A. Scott
Date Issued
2012
PURL
http://purl.flvc.org/fau/fd/FAUIR000163
Format
Citation
Neural correlates of rhythmic auditory stimulation and rhythmic movement: Rate dependence and transient to steady-state transition
Title
Neural correlates of rhythmic auditory stimulation and rhythmic movement: Rate dependence and transient to steady-state transition.
Creator
Carver, Frederick White, Florida Atlantic University, Kelso, J. A. Scott, Fuchs, Armin
Abstract/Description
The experiments in this dissertation were designed to produce a systematic characterization of the neuroelectric and neuromagnetic correlates of isochronous tone stimulation and simple rhythmic movements over a broad range of rates. The goal was to determine how the cortical representation of rhythm changes with rate, which would provide insight into known rate-dependent differences in perceptual and coordinative abilities. Fundamental transitions in the composition of the auditory and motor...
Show moreThe experiments in this dissertation were designed to produce a systematic characterization of the neuroelectric and neuromagnetic correlates of isochronous tone stimulation and simple rhythmic movements over a broad range of rates. The goal was to determine how the cortical representation of rhythm changes with rate, which would provide insight into known rate-dependent differences in perceptual and coordinative abilities. Fundamental transitions in the composition of the auditory and motor responses were hypothesized to occur within the parameter ranges studied here, including the attenuation of major response components and a shift from discrete transient activity at low rates to continuous steady-state activity at high rates. The auditory responses were studied in separate electroencephalography (EEG) and magnetoencephalography (MEG) experiments with stimulation rates ranging from 0.5 to 8Hz. In both studies, a transition from a transient to a continuous steady-state representation of the tone sequence occurred near 2Hz. In addition, an N1m component of the transient responses disappeared at rates near 8Hz, which may indicate the border beyond which tones are no longer distinct since the response is known to be an index of novelty in the auditory environment. Moreover, in a result important for understanding how evoked activity interacts with activity already present in the cortex, the phase of ongoing 40Hz rhythms is shown to affect the amplitude of the auditory evoked 40Hz response. Rhythmic finger movement was studied using a continuation paradigm in two EEG and MEG experiments at movement rates from 0.5 to 2.5Hz. Major findings included the disappearance of activity associated with movement planning and initiation at rates above 1Hz, suggesting a transition into a steady-state motor response in which there is less direct control of individual movements by the cortex. In addition, the neural correlates of synchronization and continuation were compared, with the results showing a similar cortical organization of metronome-paced and self-paced movements. The attenuation of major response components and the development of continuous steady-state activity within the present parameter ranges indicate rate-dependent changes in the cortical representation of simple rhythms, which are proposed here to relate to known rate-dependent behavioral differences in more complex coordinative environments.
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Date Issued
2003
PURL
http://purl.flvc.org/fcla/dt/12040
Subject Headings
Electrophysiology, Auditory evoked response, Electroencephalography
Format
Document (PDF)
Spatiotemporal patterns of neural fields in a spherical cortex with general connectivity
Title
Spatiotemporal patterns of neural fields in a spherical cortex with general connectivity.
Creator
Tayefeh, Vahid, Fuchs, Armin, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description
The human brain consists of billions of neurons and these neurons pool together in groups at different scales. On one hand, these neural entities tend to behave as single units and on the other hand show collective macroscopic patterns of activity. The neural units communicate with each other and process information over time. This communication is through small electrical impulses which at the macroscopic scale are measurable as brain waves. The electric field that is produced collectively...
Show moreThe human brain consists of billions of neurons and these neurons pool together in groups at different scales. On one hand, these neural entities tend to behave as single units and on the other hand show collective macroscopic patterns of activity. The neural units communicate with each other and process information over time. This communication is through small electrical impulses which at the macroscopic scale are measurable as brain waves. The electric field that is produced collectively by macroscopic groups of neurons within the brain can be measured on the surface of the skull via a brain imaging modality called Electroencephalography (EEG). The brain as a neural system has variant connection topology, in which an area might not only be connected to its adjacent neighbors homogeneously but also distant areas can directly transfer brain activity [16]. Timing of these brain activity communications between different neural units bring up overall emerging spatiotemporal patterns. The dynamics of these patterns and formation of neural activities in cortical surface is influenced by the presence of long-range connections between heterogeneous neural units. Brain activity at large-scale is thought to be involved in the information processing and the implementation of cognitive functions of the brain. This research aims to determine how the spatiotemporal pattern formation phenomena in the brain depend on its connection topology. This connection topology consists of homogeneous connections in local cortical areas alongside the couplings between distant functional units as heterogeneous connections. Homogeneous connectivity or synaptic weight distribution representing the large-scale anatomy of cortex is assumed to depend on the Euclidean distance between interacting neural units. Altering characteristics of inhomogeneous pathways as control parameters guide the brain pattern formation through phase transitions at critical points. In this research, linear stability analysis is applied to a macroscopic neural field in a one-dimensional circular and a twodimensional spherical model of the brain in order to find destabilization mechanism and subsequently emerging patterns.
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Date Issued
2018
PURL
http://purl.flvc.org/fau/fd/FA00013119
Subject Headings
Cerebral cortex, Neural circuitry, Electroencephalography, Neural fields, Spatiotemporal patterns
Format
Document (PDF)