# Dissecting the visuomotor circuit for saccadic suppression in the mouse superior colliculus

> **NIH NIH F31** · UNIVERSITY OF COLORADO DENVER · 2022 · $34,972

## Abstract

PROJECT SUMMARY
Many species, including mice, use ballistic reorienting movements called saccades to actively explore their
environment for salient stimuli. Saccades result in a transient modification of visual perception such that it
becomes difficult to see visual stimuli which appear around the time of saccades. This phenomenon is called
saccadic suppression and it is associated with a decrease in neural activity across the visual system. Converging
lines of evidence show that this neural correlate of saccadic suppression arises from a combination of visual and
premotor mechanisms. Several studies have shown that the simulating the self-generated motion associated
with saccades is sufficient to reduce visual sensitivity in the retina and reproduces the perceptual deficits
associated with actual saccades. Complementary studies have hypothesized that the saccade motor plan is
broadcast to the visual system where it is used to suppress visual activity during the peri-saccadic epoch. This
is supported by studies which demonstrate the persistence of saccadic suppression under conditions which
minimize or preclude the effect of visual mechanisms. In this proposal, we seek to understand how the visual
and premotor components of saccadic suppression are implemented by neural circuits. We will focus our
investigation on the midbrain superior colliculus (SC), a visuomotor brain structure which has long been
suspected as the source of a corollary discharge that suppresses visual activity around the time of saccades.
We would like to add to this idea that the visual output of the retina is itself modulated by saccades. We
hypothesize that a corollary discharge of premotor activity in the SC and the peri-saccadic modulation
of retinal signals cooperate to produce suppression of visual activity in the superficial layers of the SC
around the time of saccades. In Aim 1 of the proposal, we will dissect the premotor circuitry in the SC using
optogenetics, chemogenetics, and high-density in vivo recordings of single-unit activity while mice make
saccades. In Aim 2 of this proposal, we will examine SC-projecting retinal ganglion cells for peri-saccadic
modulation using two-photon calcium imaging and naturalistic visual stimulation. Public health significance. This
proposal aims to understand how saccadic suppression is implemented by dissecting the visual and premotor
circuitry in the midbrain SC. This research will advance our understanding of the neural basis for stable and
continuous visual perception across saccades which is critical for the conduct of normal visual behavior. In
addition, this research could lead to improvements in the diagnosis and treatment of injury and diseases which
affect the oculomotor system.

## Key facts

- **NIH application ID:** 10534593
- **Project number:** 1F31EY033651-01A1
- **Recipient organization:** UNIVERSITY OF COLORADO DENVER
- **Principal Investigator:** Joshua B Hunt
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $34,972
- **Award type:** 1
- **Project period:** 2022-09-01 → 2026-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10534593

## Citation

> US National Institutes of Health, RePORTER application 10534593, Dissecting the visuomotor circuit for saccadic suppression in the mouse superior colliculus (1F31EY033651-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10534593. Licensed CC0.

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