# Optogenetic dissection of inter-hemispheric frontal eye field circuits for eye movements

> **NIH NIH R21** · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · 2022 · $249,192

## Abstract

Abstract
Visual-motor transformations and the generation of eye movements require processing that
occurs in both brain hemispheres simultaneously. It is often assumed that the uninterrupted
transfer of information from one hemisphere to the other and the resolution of competing
movement plans are trivial problems. Yet this is unlikely the case because many visual-motor
disorders have been linked to dysfunctions in inter-hemispheric communication, including
strabismus, amblyopia, neglect, and epilepsy. Thus, inter-hemispheric communication is an
understudied but central part of brain function.
The ability to record from both hemispheres simultaneously and identify the exact neuronal
connections between them has traditionally been difficult to accomplish. However, we recently
developed optogenetic tools that reliably locate and label the cross-hemisphere inputs to a
particular brain region. Coupled with modern techniques for recording neuronal populations, this
approach promises to usher in a new era of primate-centric research that maps the brain
circuitry needed to combine cortical activity in both hemispheres to generate an unambiguous
percept and plan a specific action.
The ability to directly link neuronal connections between brain hemispheres with their functional
role in visual-motor behavior provides a powerful tool for investigating the longstanding
hypothesis that activity for a specific movement vector in one hemisphere inhibits dissimilar
movement activity in the other. We propose experiments that test this hypothesis by capitalizing
on the well-characterized, precisely measurable, and naturalistic nature of eye movements and
their cortical control by the frontal eye fields (FEF). In our first specific aim, we will optically
identify and activate neurons in one FEF that project across the hemispheres while recording
from recipient neurons in the other FEF to determine whether increased activity in one
hemisphere decreases the activity of recipient neurons with dissimilar direction preferences in
the other hemisphere. Our second specific aim will use a similar setup but inhibit the activity of
cross-hemisphere cortical inputs to more thoroughly test the network architecture that governs
inter-hemispheric communication. Collectively, the proposed experiments will: 1) identify cortical
mechanisms for cross-hemispheric coordination during natural vision and eye movements, in
preparation for future work on interhemispheric cortical communication; 2) establish a precise,
reliable tool for identifying cortical inputs to greatly improve the mapping of cortical circuitry.

## Key facts

- **NIH application ID:** 10527512
- **Project number:** 1R21EY033460-01A1
- **Recipient organization:** UNIVERSITY OF PITTSBURGH AT PITTSBURGH
- **Principal Investigator:** Joseph Patrick Mayo
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $249,192
- **Award type:** 1
- **Project period:** 2022-09-30 → 2024-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10527512

## Citation

> US National Institutes of Health, RePORTER application 10527512, Optogenetic dissection of inter-hemispheric frontal eye field circuits for eye movements (1R21EY033460-01A1). Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/grant/nih/10527512. Licensed CC0.

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