# Organization and Function of Visual Cortical Feedback Systems

> **NIH NIH R01** · SALK INSTITUTE FOR BIOLOGICAL STUDIES · 2020 · $642,755

## Abstract

Project Summary
Visual perception is mediated by complex interactions amongst neurons in the retina, visual cortex, and
subcortical brain structures. The importance of vision to humans and other primates is reflected in the
enormous percentage of cerebral cortex devoted to processing visual information. Thus, deficits in visual
processing are particularly debilitating and arise from abnormalities not only in the eye, but also in cortical
circuitry. For example, strabismus or amblyopia during childhood can have long-lasting effects on the cortical
circuits that process visual information. There is also evidence that some forms of dyslexia result from central
visual system abnormalities. The function of the nervous system is dependent on complex interactions
between networks of neurons composed of multiple neuron types across multiple cortical areas. The proposed
studies are aimed at revealing the organization and functional impact of local and long-distance feedback
connections within and between mouse visual cortical areas. These studies are conducted in mice to take
advantage of the range of molecular, genetic, and viral tools that can be used to elucidate brain circuits and
link them to function using optogenetic and imaging methods. The 2 aims will reveal: the fine-scale
organization of V1 microcircuits linking cortical layers 2/3 and 5, and the functional impact of feedback from
layer 5 to layer 2/3; and the organizational principles and functional impact of cortico-cortical feedback.

## Key facts

- **NIH application ID:** 9979896
- **Project number:** 5R01EY022577-09
- **Recipient organization:** SALK INSTITUTE FOR BIOLOGICAL STUDIES
- **Principal Investigator:** EDWARD M CALLAWAY
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $642,755
- **Award type:** 5
- **Project period:** 2012-05-01 → 2022-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9979896

## Citation

> US National Institutes of Health, RePORTER application 9979896, Organization and Function of Visual Cortical Feedback Systems (5R01EY022577-09). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9979896. Licensed CC0.

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