# Viral Strategies for Functional Connectomics in the Visual System

> **NIH NIH R01** · ALLEN INSTITUTE · 2020 · $902,821

## Abstract

Project Summary / Abstract
 A fundamental but unsolved question in neuroscience is how specific connections between brain cells
(neurons) underlie information processing. Circuits in the cerebral cortex—the part of the mammalian brain
that underlies high-level sensory, motor, and cognitive function—consists of tens of thousands of neurons,
each of which sends and receives thousands of connections. Perhaps the biggest reason we don't understand
the cerebral cortex is that we don't have an actual wiring diagram of any single cortical circuit. But even if we
had a wiring diagram, we would need to know what each neuron in a circuit is doing: its physiology. In this
proposal, we plan study the functional logic of networks in the visual cortex by examining groups of connected
neurons whose responses to visual stimuli have been characterized.
 We will combine two techniques to tackle this difficult problem. Connections between neurons will be
determined with a modified virus that allows us to specifically labels ensembles of neurons, all of which
connect with a single 'target' neuron in each experiment. Once the neurons are labeled, we will use an
advanced form of scanning-laser imaging (calcium imaging with two-photon microscopy) that allows us to
make movies of each neuron's activity in response to carefully chosen visual stimuli. Together, these tools
will allow to probe the functional logic of cortical circuits: the relationship between neuronal function and the
wiring between neurons.
 The cerebral cortex is a network of networks. There are many different cortical regions each of which
has its distinct inputs and outputs and distinct physiological properties. For instance, roughly ten visual cortical
areas process different aspects of visual stimuli. We will start by studying the functional logic of wiring within
three visual cortical areas: V1, AL and PM. We will then examine the functional logic of connections between
these areas. The viral strategy that we employ is currently the only method that allow for both local and inter-
areal connection to be studied along with physiology. The data we collect will help us understand feedforward,
lateral, and feedback connections in cortical circuits and will form the foundation of new, data-driven models
of cortical function.

## Key facts

- **NIH application ID:** 9983837
- **Project number:** 5R01NS104949-04
- **Recipient organization:** ALLEN INSTITUTE
- **Principal Investigator:** R Clay Reid
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $902,821
- **Award type:** 5
- **Project period:** 2017-09-25 → 2022-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9983837

## Citation

> US National Institutes of Health, RePORTER application 9983837, Viral Strategies for Functional Connectomics in the Visual System (5R01NS104949-04). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/9983837. Licensed CC0.

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