The Role of Areas V1 and V2 in Target Selection

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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.