Grant Number: 5R01EY005603-22
Project Title: Cortical Processing of Visual Motion
PI Information: PROFESSOR WILLIAM T. NEWSOME,
The long-term goal of this research is to understand the neural
mechanisms underlying simple forms of visually based cognition,
including visually based decision-making in particular. The projects
will focus on a network of high-level brain structures that appears to
translate perception of the visual world into plans for action.
Prior studies indicate that this network includes cortical areas of
the parietal and frontal lobes as well as midbrain structures such as
the superior colliculus. A similar network of structures is present in
humans, and the proposed research is thus likely to contribute directly
to our developing knowledge of human vision, cognition, and their
clinical disorders. Three specific aims will be pursued during the
coming grant period:
1. Electrical micro-stimulation techniques will be employed to test
rigorously the causal role played by each candidate neural structure in
visually-based decision making.
2. Combined stimulation and recording techniques will be employed to
test specific hypotheses concerning the functional circuitry that
connects these areas and the information that flows between them.
3. Electrophysiological techniques will be employed to study identify
and study the neural mechanisms that compute the "subjective value" that
an organism places on alternative actions.
Psychological and economic studies have shown that perceived value
exerts an enormous influence on decision making. Together the proposed
experiments will provide considerable impetus toward understanding the
neural mechanisms underlying a simple form of cognition.
The ultimate health-related value of this work will follow from an
understanding of the biological basis of mental function. Neurological
and psychiatric diseases that affect mental function take a massive toll
on the health and well-being of our citizenry. These diseases are
particularly insidious because they slowly rob the afflicted person of
normal cognitive abilities - the very essence of personal identity.
Understanding how brain activity gives rise to mental function in
normal subjects will undoubtedly provide a deeper understanding of what
goes wrong in various disease processes, and suggest useful therapeutic
approaches for such diseases.
cognition, motion perception, neural information processing, vision
biological signal transduction, decision making, frontal lobe /cortex,
Macaca, behavior test, electrophysiology
Institution: STANFORD UNIVERSITY, STANFORD, CA 94305
Fiscal Year: 2006
Project Start: 01-JAN-1985
Project End: 31-JUL-2008
ICD: NATIONAL EYE INSTITUTE
Journal of Vision
Volume 5, Number 7, Article 1, Pages 603-621 doi:10.1167/5.7.1
http://journalofvision.org/5/7/1/ ISSN 1534-7362
Cone signal interactions in direction-selective
neurons in the middle temporal visual area (MT)
Crista L. Barberini, Marlene R. Cohen, Brian A. Wandell, William T.
We conducted experiments in two adult rhesus monkeys (Macaca mulatta,
both female, weight 7–10 kg). Before the experiments, we surgically
implanted each animal with a head-holding device (Evarts, 1968), a
scleral search coil for measuring eye movements (Judge, Richmond, & Chu,
1980), and a recording cylinder (Crist Instruments, Damascus, MD) that
provided access to MT. During experiments, the animals sat in a primate
chair with their heads restrained, facing a CRT display.
The animals performed a fixation or discrimination task for liquid
rewards while visual stimuli were presented within the receptive field
of a single MT neuron. All surgical and behavioral procedures conformed
to guidelines established by the U.S. Department of Health and Human
Services (National Institutes of Health) in the Guide for the Care
and Use of Laboratory Animals (1996).
The Journal of Neuroscience, July 26, 2006, 26(30):7779-7790;
Local Field Potential in Cortical Area MT: Stimulus
Tuning and Behavioral Correlations
Jing Liu and William T. Newsome
Howard Hughes Medical Institute and Department of Neurobiology,
Stanford University School of Medicine, Stanford, California 94305-5125
Monkey maintenance and surgery. We conducted extracellular
recordings in three hemispheres of two macaque monkeys (Macacca mulatta),
one male and one female. Before the experiments, the monkeys were
surgically implanted with a head-holding device and recording cylinder (Crist
Instruments, Hagerstown, MD) and a scleral search coil for monitoring
All implanted devices were magnetic resonance imaging compatible.
Surgical, animal care, and experimental procedures conformed to
guidelines established by the National Institutes of Health and were
approved in advance by the Stanford University Institutional Animal Care
and Use Committee.
Visual stimuli. During each experimental session, the monkey
was seated in a primate chair with its head fixed. The monkey viewed
visual stimuli on a cathode ray tube monitor at a distance of 57 cm.
Visual stimuli were drawn with a VSG graphics board (Cambridge Research
Systems, Kent, UK); the frame rate of the monitor was 160 Hz.