Grant Number: 5R01EY012816-07
Project Title: Quantitative Studies of Cortical Visual Processing
PI Information: ASSOCIATE PROFESSOR DARIO L. RINGACH,
[email protected]
Abstract: DESCRIPTION (provided by applicant):
The objective of this proposal is to understand the nature of ongoing
cortical activity, what it represents, and how it interacts with
external stimuli to generate a "real-time" response in primary visual
cortex.
We propose to use micro-machined electrode arrays to simultaneously
record local-field potentials and single-unit activity, in combination
with novel methods of mathematical analysis, to perform the following
studies:
(a) to measure and mathematically model the dynamics of cortical
activity, in spontaneous and stimulus evoked regimes. We will test the
hypothesis that cortical activity is structured and can be represented
in a low-dimensional space. Novel mathematical models will be developed
that predict population responses on a trial-to-trial basis.
(b) To determine how populations of neurons represent distributions
of physical attributes (such as orientation) within a local area of the
visual field. We will test the hypothesis that dynamic switching among
cortical states is involved in the representation of orientation
distributions.
(c) To measure, and mathematically model, the response of the
cortical population to electrical stimulation through individual or
groups of electrodes. The resulting model will be used in the design of
a real-time controller of cortical activity.
Given a pattern of cortical activity as a "target", we will test our
ability to bring the population response into the target pattern via
electrical stimulation. We will develop safe stimulation protocols by
constraining the spatio-temporal pattern of electrical stimulation
across the electrode array.
The significance of the proposed work is its contribution to
understanding the cortex as a "real-time" processing device. The
findings will reveal how ongoing activity is structured, and how it
combines with incoming visual stimulation to generate a response on a
trial-by-trial basis.
We will advance our basic knowledge of cortical function by
investigating how neural populations represent distributions of physical
attributes within a local region of the visual field.
Finally, the techniques and methods developed here will be
instrumental in the design of cortical prostheses for the restoration of
sensory function, which require the activity of a large population of
neurons to be controlled using a limited number of stimulating
electrodes.
Thesaurus Terms:
brain electrical activity, neural information processing, neural
transmission, visual cortex, visual stimulus electrostimulus, evoked
potential, mathematical model, method development, model design
/development, neuroanatomy, time resolved data, visual field Macaca
fascicularis, computer data analysis, electrophysiology, microelectrode
Institution: UNIVERSITY OF CALIFORNIA LOS ANGELES
Office of Research Administration
LOS ANGELES, CA 90095
Fiscal Year: 2006
Department: NEUROBIOLOGY
Project Start: 01-FEB-2000
Project End: 31-JAN-2010
ICD: NATIONAL EYE INSTITUTE
IRG: CVP
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