# Organization and Function of Visual Cortical Feedback Systems

> **NIH NIH R01** · SALK INSTITUTE FOR BIOLOGICAL STUDIES · 2023 · $583,028

## 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 and
subcortical 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 and
subcortical areas. General principles about cortical feedback connections and corticothalamic networks
learned from studies of the mouse visual system are likely to also apply to circuits mediating cognitive
functions and may be impaired in disorders such as autism and schizophrenia. The proposed studies are
aimed at revealing the organization and functional impact of: 1) cortical feedback connections to the primary
visual cortex; and 2) cortico-thalamo-cortical circuits. 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 4 aims will reveal: 1) the functional impact of feedback
from layers 2/3 or layer 5 of cortical areas AL and PM to V1; 2) how feedback from layers 2/3 or layer 5 of
cortical areas AL and PM to V1 integrate with specific inhibitory circuits within V1; 3) the input-output
relationships of neurons in the pulvinar nucleus of the thalamus that project to identified visual cortical areas; 4)
the functional impact of pulvinar inputs to the visual cortex.

## Key facts

- **NIH application ID:** 10659093
- **Project number:** 2R01EY022577-11A1
- **Recipient organization:** SALK INSTITUTE FOR BIOLOGICAL STUDIES
- **Principal Investigator:** EDWARD M CALLAWAY
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $583,028
- **Award type:** 2
- **Project period:** 2012-05-01 → 2028-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10659093

## Citation

> US National Institutes of Health, RePORTER application 10659093, Organization and Function of Visual Cortical Feedback Systems (2R01EY022577-11A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10659093. Licensed CC0.

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