# Imaging Functional Connectivity in Visual Cortex

> **NIH NIH R01** · COLUMBIA UNIV NEW YORK MORNINGSIDE · 2021 · $384,357

## Abstract

The mammalian visual cortex is critical for vision and has been used as a model
for the rest of the cerebral cortex. In spite of this, little is known about the detailed
operations of its microcircuits. In fact, the cortex is composed of many different
cell types, and, it is likely that each cell type has a particular circuit function.
 In the past cycle we focused on four major subtypes of cortical GABAergic
interneurons (PV, SOM, VIP and chandeliers) in mouse visual cortex, using two-
photon photoactivation and transgenic mice to map connections to and from
interneurons in a systematic fashion. We found that interneurons often make
synaptic connections with every single neighboring cell, and this promiscuity
could be an important feature of the cortical inhibitory “circuit blueprint”.
 In the course of these experiments we unexpectedly discovered that groups of
coactive neurons, which we termed “neuronal ensembles”, account for the
majority of the cortical response to visual stimuli. Moreover, ensembles also
dominate spontaneous activity and have distinct spatiotemporal characteristics.
Further, using two-photon optogenetics we found by chance that ensembles can
be artificially imprinted into the cortex and they can be recalled by stimulating
individual neurons, showing pattern completion, even days after imprinting.
These intriguing results suggest that ensembles could be multicellular building
blocks of cortical function, implementing a population neural code.
 To pursue this discovery and test these ideas we now propose an experimental
“deep dive” into the properties of these ensembles, in order to characterize their
basic phenomenology, understand their synaptic circuit mechanisms and test
their role in the behavior of the animal in sensory discrimination. The project will
be carried out in primary visual cortex of awake behaving mice and make use of
a novel two-photon holographic microscopy method that enables us to image and
optically manipulate neurons in different cortical layers simultaneously.
 Our work will provide a systematic anatomical and functional description of
neuronal ensembles, how they regulate the activity of the cortex and how they
can be manipulated and reconfigured. This could help in novel therapeutic
strategies by reconfiguring pathological circuits and correct visual deficits.

## Key facts

- **NIH application ID:** 10169447
- **Project number:** 5R01EY011787-20
- **Recipient organization:** COLUMBIA UNIV NEW YORK MORNINGSIDE
- **Principal Investigator:** RAFAEL YUSTE
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $384,357
- **Award type:** 5
- **Project period:** 1998-01-01 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10169447

## Citation

> US National Institutes of Health, RePORTER application 10169447, Imaging Functional Connectivity in Visual Cortex (5R01EY011787-20). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10169447. Licensed CC0.

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