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Grant Number: 5R01EY014924-03
Project Title: Interaction of Visual and Oculomotor Signals in
Cortex
PI Information: TIRIN MOORE,
tirin@stanford.edu
Abstract:
Visual spatial attention is a critical mental operation that allows us
to selectively process only relevant information in the face of an
overabundance of visual input. Understanding the underlying neural
mechanisms of this phenomenon is central to our understanding of the
neural basis of cognition and central to any hope of ameliorating
disorders of attention in human patients.
Ours and other recent work suggests that better knowledge of the
interplay between visual and oculomotor mechanisms may be the key to
establishing a causal neural basis of spatial attention. Thus, the
long-term goal of this proposal is to understand the reciprocal
interactions between oculomotor and vision mechanisms in the primate
brain. This goal will be pursued via the following three aims:
Our first aim is to test the causal role of frontal cortical saccade
mechanisms in directinq covert spatial attention and in drivinq
selection in visual cortex. Neuronal activity within the frontal eye
field (FEF) will be inactivated pharmacologically and we will examine
the effect of this on the ability of monkeys to voluntarily direct
attention covertly to the affected part of space, and on the degree to
which the widely observed neural correlates of attention in extrastriate
area V4 are eliminated.
Our second aim is to compare the changes in visual qain observed in
extrastriate cortex during FEF microstimulation with the known effects
of covert spatial attention. We will examine how the changes in V4
responses caused by subthreshold FEF microstimulation in passively
fixating monkeys parallel the modulations observed in animals trained to
direct covert attention voluntarily.
Our third aim is to examine the relationship between the probability
that a saccade will be made to a visual stimulus and the gain of visual
cortical responses to that stimulus. We will directly manipulate saccade
probability by systematically varying the parameters of FEF
microstimulation and study the effect of this manipulation on the gain
of visual responses in area V4.
This research may provide insight into the physiological basis of
disorders of attention in humans, which affect up to 5% of children in
the U.S, and may also provide insight into problems of visual-oculomotor
coordination, such as dyslexia, which affects approximately 10% of U.S.
citizens.
Thesaurus Terms:
attention, neural information processing, neuropsychology,
neuroregulation, psychomotor function, saccade, visual cortex, visual
pathway, visual perception, visual threshold brain electrical activity,
visual stimulus, visual tracking Macaca fascicularis, Macaca mulatta,
behavior test
Institution: STANFORD UNIVERSITY, STANFORD, CA 94305
Fiscal Year: 2006
Department: NEUROBIOLOGY
Project Start: 20-SEP-2004
Project End: 31-JUL-2009
ICD: NATIONAL EYE INSTITUTE
IRG: CVP
Published online before print May 21, 2007, 10.1073/pnas.0701104104
PNAS | May 29, 2007 | vol. 104 | no. 22 | 9499-9504
BIOLOGICAL SCIENCES / NEUROSCIENCE
Rapid enhancement of visual cortical response
discriminability by microstimulation of the frontal eye field
Katherine M. Armstrong* and Tirin Moore
Department of Neurobiology, Stanford University School of Medicine,
Stanford, CA 94305
Communicated by Charles G. Gross, Princeton University, Princeton,
NJ, February 8, 2007 (received for review November 19, 2006)
Methods
General and Surgical Procedures. Four male monkeys (two Macaca
mulatta and two Macaca fascicularis, 4–10 kg) were used in these
experiments. All experimental procedures were in accordance with
National Institutes of Health Guide for the Care and Use of Laboratory
Animals, the Society for Neuroscience Guidelines and Policies, and
Stanford University Administrative Panel on Laboratory Animal Care.
General experimental and surgical procedures have been described
previously (45). Each animal was surgically implanted with a head post,
a scleral eye coil, and two recording chambers. Surgery was conducted by
using aseptic techniques under general anesthesia (isoflurane), and
analgesics were provided during postsurgical recovery. Two craniotomies
were performed on each animal, allowing access to dorsal V4, on the
prelunate gyrus, and FEF, on the anterior bank of the arcuate sulcus.
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