# The origins of neuronal correlations in cerebral cortex

> **NIH NIH RF1** · UNIVERSITY OF CHICAGO · 2021 · $1,980,581

## Abstract

Project Summary
Here, we propose to thoroughly characterize the origins of pairwise correlations in cortex using a synergistic mix
of experimental methodologies, behavior, and computation in mice and macaques. We will elucidate the
mechanistic underpinnings of normalization and test our hypothesis that changes in cortical pairwise correlations
and other signature arise from ongoing cortical computations. In Aim 1 we will record from populations of neurons
in the middle temporal visual area of trained, behaving monkeys to test the hypothesis that pairwise spike
correlations, gamma oscillation and transient responses at the onset of visual stimuli arise in part from the
dynamics of the circuits that normalize neuronal responses. These tests require measurements with a precision
that is not feasible in mice. Conversely, the experiments in Aim 2 and 3 address questions that are not feasible
in monkeys. In Aim 2 we will exploit the accessibility of mouse visual cortex by using both two-photon laser
scanning microscopy and multielectrode arrays to comprehensively measure the relationship between
normalization and pairwise correlations in populations of V1 neurons and measure how spatial separation within
cerebral cortex affects that relationship. Finally, in Aim 3 we will establish the contributions of specific cell classes
to normalization and pairwise correlations in mouse V1. We record the activity of pyramidal neurons and the
three most thoroughly characterized classes of cortical interneuron (VIP, SST and PV) during normalization. We
will then separately manipulate the activity of these cells classes to revealing the role that changes to the ratio
of excitation and inhibition play in driving normalization. In this way, we will establish the role these neurons play
in changing pairwise correlations within the excitatory pool of neurons. Results from all three Aims will be tied
together using a new family of dynamic, recurrent circuit models of normalization to formalize the hypothesis that
normalization imposes pairwise correlations and other activity signatures, and will use experimental data to
constrain and refine these models.

## Key facts

- **NIH application ID:** 10205571
- **Project number:** 1RF1NS121772-01
- **Recipient organization:** UNIVERSITY OF CHICAGO
- **Principal Investigator:** DAVID J HEEGER
- **Activity code:** RF1 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $1,980,581
- **Award type:** 1
- **Project period:** 2021-04-15 → 2024-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10205571

## Citation

> US National Institutes of Health, RePORTER application 10205571, The origins of neuronal correlations in cerebral cortex (1RF1NS121772-01). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10205571. Licensed CC0.

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