# Investigating the distribution and timing of pre-saccadic modulation across cortical layers in MT and the influence of FEF signals

> **NIH NIH F31** · UNIVERSITY OF ROCHESTER · 2024 · $48,974

## Abstract

PROJECT SUMMARY:
Attention leads eye movements producing perceptual enhancements at the saccade targets immediately prior
to saccades1-3. Pre-saccadic attention has been related to enhanced neural responses before saccades made
into a neuron’s receptive field, but much remains unknown about the underlying neural pathway. It is known
that stimulation to one prefrontal saccadic control center, FEF, leads to pre-saccadic enhancements in extra-
striate cortex4 Here we’re specifically interested in the laminar distributions and timing of pre-saccadic
enhancements in visual cortex and how FEF cortical feedback projections influence these factors. We
hypothesize that if direct FEF feedback drives pre-saccadic attention that it will exert stronger and earlier
latency modulation of neural responses in superficial and deep layers of visual cortex.
To test this hypothesis, we will record from marmoset area MT/MTC, an early visual area with strong selectivity
for stimulus motion. We will record from neural populations with laminar recording arrays. Preliminary data
support that we are able to distinguish between cortical layers and make rudimentary cell class distinctions of
narrow and broad spiking cells using linear arrays. Based on the distribution of FEF feedback to MT/MTC, we
expect to see higher and earlier modulation due to saccade planning in the superficial and deep layers as
opposed to input layers. Furthermore, I propose to investigate FEF’s role in pre-saccadic enhancements seen
in MT/MTC with optogenetic manipulation (AAV-DLX-ChR2 virus) to reversibly inactivate FEF within brief
temporal epochs (25 ms pulses) preceding saccades. We expect to see changes to eye movements, including
impairment of post-saccadic smooth eye movements that predictively follow target motion due to pre-saccadic
selection. More so, we expect to see decreased pre-saccadic enhancements in MT/MTC when optogenetic
light stimulation occurs in the 100ms preceding the saccade coincident with the period of motor build-up
activity in FEF. These experiments will shed light on the micro- (cell class distribution and laminar distinctions)
and macro- (FEF feedback) level of the circuitry controlling pre-saccadic enhancements in visual cortex. The
training during this project will focus on increasing proficiency in computational analysis as well as improving
experimental techniques and professional development for a career as a future independent investigator,
under the guidance of Jude Mitchell, a leading researcher on visual perception and attention, and Dr. Kuan
Wang, an expert in cortical circuits involved in the cognitive and affective control of behaviors.

## Key facts

- **NIH application ID:** 10994768
- **Project number:** 1F31EY035866-01A1
- **Recipient organization:** UNIVERSITY OF ROCHESTER
- **Principal Investigator:** Amy Beatrice Bucklaew
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $48,974
- **Award type:** 1
- **Project period:** 2024-09-01 → 2026-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10994768

## Citation

> US National Institutes of Health, RePORTER application 10994768, Investigating the distribution and timing of pre-saccadic modulation across cortical layers in MT and the influence of FEF signals (1F31EY035866-01A1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10994768. Licensed CC0.

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