Grant Number: 5R01EY014884-03
Project Title: The Role of Areas V1 and V2 in Target Selection
PI Information: PROFESSOR AND DIRECTOR PETER H. SCHILLER, phschill@mit.edu

Abstract: DESCRIPTION (provided by applicant):
This is a revised application that has taken into account the comments of the referees who have evaluated the initial submission of the grant. In a separate section, a point-by-point response is made to the criticisms. The Preliminary Studies section has been expanded to include a series of pilot experiments we had carried out the past six months that deal with the central criticisms advanced by the referees and provide evidence that the projects proposed are feasible and are likely to lead to significant new understanding of the role areas V1 and V2 play in target selection with visually guided eye movements. This grant application replaces EY00676 entitled Parallel information processing in the visual system that we decided not to renew because the work under that grant has been largely completed and because the new discoveries we had made dictate a shift in our effort. The aim of the proposed research is to determine what role areas V1 and V2 of the primate play in the selection of visual targets with saccadic eye movements. Rhesus monkeys will be trained on a variety of behavioral tasks to enable us to study their visual capacities and their ability to select visual targets with saccadic eye movements. Single-cell recordings, microstimulation, and the application of GABAergic neurotransmitter agonists and antagonists will be used to assess how areas V1 and V2 interact and how they contribute to the generation of saccadic eye movements to visual targets. The proposal is based on a recent set of findings from our laboratory that has established that these two areas are centrally involved in target selection with visually guided saccadic eye movements. The work has shown that electrical stimulation of the infragranular layers of V1 and V2 enhances the generation of saccadic eye movements to visual targets at very low current levels whereas stimulation of the supragranular layers interferes with target selection. In addition to clarifying the role of V1 and V2 in the generation of visually guided saccadic eye movements, the proposed research should have significant bearing on microstimulation prosthetics for the visually disadvantaged as it will specify the effects of microstimulation of different layers of the visual cortex and what roles various neurotransmitters play in the process.

Thesaurus Terms:
saccade, visual cortex
biofeedback, gamma aminobutyrate, neurotransmitter agonist, neurotransmitter antagonist, superior colliculus, visual perception
Macaca mulatta, behavior test, electrostimulus

Institution: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
77 MASSACHUSETTS AVE
CAMBRIDGE, MA 02139
Fiscal Year: 2006
Department: CENTER FOR CANCER RESEARCH
Project Start: 01-APR-2004
Project End: 31-MAR-2009
ICD: NATIONAL EYE INSTITUTE
IRG: CVP

Volume 16, Number 22, Issue of November 15, 1996 pp. 7376-7389
Copyright ©1996 Society for Neuroscience

Contextual Modulation in Primary Visual Cortex

Karl Zipser¹, Victor A. F. Lamme², and Peter H. Schiller<sup>1

1</sup> The Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, and ² Graduate School of Neurosciences, Department of Medical Physics, AMC, University of Amsterdam, Amsterdam, The Netherlands, and The Netherlands Ophthalmic Research Institute, 1100 AC Amsterdam, The Netherlands

MATERIALS AND METHODS
Experiments were performed on four male Macaca mulatta, each weighing 8-10 kg. Before surgery, monkeys were trained to jump into their primate chairs and were habituated to the laboratory environment. Subsequently, each animal underwent surgical procedures for implantation of a stainless steel cranial post for fixing the position of the head. In the same operation, we implanted the given animal with a scleral coil for monitoring eye position. All surgical procedures were performed using sterile techniques, with monkeys under deep pentobarbital anesthesia; all experimental procedures were performed in accordance with National Institutes of Health guidelines.

After recovery from surgery, monkeys were water-deprived and brought to the laboratory for training. We used a PDP-11/37 computer to regulate and monitor the monkey's behavioral tasks, to collect behavioral and neurophysiological data, and to signal an IBM PC for control of visual stimulation. With its head restrained in the primate chair facing a computer graphics monitor, each monkey was trained to fixate a small luminous spot on the screen and then to make a saccadic eye movement to a luminous target stimulus that appeared in a random position when the fixation spot was extinguished. Analog x and y eye position signals, measured using the scleral coil (Robinson, 1963 ), were collected at 200 Hz and digitized with a precision of 0.01° of visual angle. For maintaining fixation and then making the correct saccades, the monkey was rewarded automatically with a drop of apple juice. During training and recording, animals drank a total of 300-500 ml of juice (during 1500 or more trials) per session. Additional rewards of peanuts and fresh fruit were provided once the animals returned to their home cages at the end of the day.