# Excitation and Inhibition in Neural Circuits of the Visual Cortex

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA BERKELEY · 2021 · $475,554

## Abstract

PROJECT SUMMARY
Neural circuits of the primary visual cortex (V1) are critical for generating perceptions of our external world. In
V1, most neurons exhibit potent modulation by stimuli that are outside their receptive fields, a process termed
‘surround modulation’. Importantly, the magnitude and sign of surround modulation depend on the orientation
and contrast of the center and surround – leading to the notion that flexible surround modulation contributes to
scene segmentation, salience detection, contour integration, and figure/ground segregation. The specific
neural circuits in V1 that explain the feature dependence of surround modulation are largely unknown. By
combining intracellular and extracellular electrophysiology, two photon imaging, and optogenetics in awake
mice, we aim to reveal the inhibitory circuits in V1 that can account for these fundamental features of V1
computation. Specifically, we will test the hypothesis that a competitive inhibitory interaction between two types
of V1 GABAergic interneurons (‘SST’ and ‘VIP’) cells, provides a circuit and synaptic basis for the feature
dependence of surround modulation. We will image the visual responses of these two subtypes, then
manipulate them optogenetically while recording neural activity extracellularly, or synaptic currents
intracellularly, to test whether their visual responses and network impact are consistent with key roles in the
orientation and contrast dependence of surround modulation. These experiments will provide critical new
insight into how cortical inhibitory circuits mediate key aspects of sensory perception.

## Key facts

- **NIH application ID:** 10222689
- **Project number:** 5R01EY023756-08
- **Recipient organization:** UNIVERSITY OF CALIFORNIA BERKELEY
- **Principal Investigator:** Hillel Adesnik
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $475,554
- **Award type:** 5
- **Project period:** 2013-09-01 → 2024-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10222689

## Citation

> US National Institutes of Health, RePORTER application 10222689, Excitation and Inhibition in Neural Circuits of the Visual Cortex (5R01EY023756-08). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10222689. Licensed CC0.

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