# Circuits for contextual modulation in V1

> **NIH NIH U19** · COLUMBIA UNIVERSITY HEALTH SCIENCES · 2021 · $365,148

## Abstract

Our current mechanistic understanding of sensory representation in primary visual cortex (V1) is
principally “feed-forward”. That is, the spatio-temporal structure of the receptive field (RF) of V1
neurons results from the combination of receptive filed elements transmitted by earlier stages of
visual processing (i.e. retina and thalamus), in a feed-forward manner. While computational
models based on this feed-forward understanding of V1 are relatively accurate at predicting the
response of neurons to visual stimuli presented within the borders of the neuron’s RF, they
generally fail when the stimuli exceed the size of the RF, as is the case for every-day visual
scenes that encompass the entire field of view. One of the main reason for the inability of current
models to predict responses of V1 neuron to naturalistic stimuli is that the response of neurons in
V1 to stimuli in their RF is strongly modulated by what happens outside of their RF. In other words,
how neurons in V1 respond to a stimulus presented in their RF depends on the context or
“surround” within which the stimulus is presented. In the natural world, visual stimuli falling in the
RF of a V1 neuron are never devoid of a surround. Consistent with these neurophysiological
observations, psychophysical experiments in humans and animals show that the perception of a
visual stimulus depends on its relationship to the surrounding visual context. Thus, the ability to
process visual information depending on the context is a key property of visual cortex and has a
profound impact on how we perceive the world. Only a clear mechanistic, circuit level
understanding of how the context modulates the response of V1 will allow us generate realistic
models capable of accurately predicting the response of this area to naturalistic stimuli.
Neurophysiological data indicate that contextual modulation of neuronal responses in V1 most
likely relies on intra-cortical interactions. That is, while the classical RF structure of a V1 neuron
results from a feed-forward process, the modulation by the surround likely depends on intra-
cortical circuit elements, their connectivity pattern and their dynamic interactions. This proposal
aims at elucidating these cortical circuit elements and how their interaction gives rise to the
contextual modulation of the response to visual stimuli in V1. A thorough mechanistic
understanding of contextual modulation in V1 will allow us to build realistic models capable of
capturing the response of visual cortex to naturalistic stimuli. Thus, data obtained from this
proposal will be essential in informing and validating realistic models of V1.

## Key facts

- **NIH application ID:** 10231007
- **Project number:** 5U19NS107613-04
- **Recipient organization:** COLUMBIA UNIVERSITY HEALTH SCIENCES
- **Principal Investigator:** MASSIMO SCANZIANI
- **Activity code:** U19 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $365,148
- **Award type:** 5
- **Project period:** 2018-09-15 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10231007

## Citation

> US National Institutes of Health, RePORTER application 10231007, Circuits for contextual modulation in V1 (5U19NS107613-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10231007. Licensed CC0.

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