# CRCNS: Dissecting Directed Interactions Amongst Multiple Neuronal Populations

> **NIH NIH R01** · CARNEGIE-MELLON UNIVERSITY · 2024 · $338,510

## Abstract

Nearly all brain functions involve activity that is distributed across multiple areas. To understand these 
functions, it is critical to understand the flow of signals across this distributed network. To date approaches 
to understanding inter-areal signaling have been limited in several critical ways. First, they often focus on 
single neurons or a few voxels to summarize an area’s activity—an impoverished sample of the intricate 
neuronal population activity patterns that are known to represent and transmit information. Second, prior 
approaches often consider only pairwise inter-areal interactions, though the relevant network of areas is 
often much larger. Third, they rarely consider the concurrent flow of signals both from and to any given 
node in the network. In this project, we aim to overcome all three of these limitations. In Aim 1, we will 
develop and validate statistical methods that allow us to assess the directed, multi-dimensional flow of 
neuronal population signals among multiple (more than two) brain areas. We will identify directed 
interactions based on if the activation of a population activity pattern in one brain area tends to reliably 
precede the activation of a population activity pattern in another brain area with a consistent time delay. In 
Aim 2, we will refine and deploy the methods we develop to assess signal flow across multiple stages of 
the macaque visual system, an ideal testbed given a great deal of prior work on the anatomical and 
functional properties of the sampled areas. Specifically, we will record hundreds of neurons distributed 
across different layers of primary visual cortex (V1), V2, and V3. We will determine how columnar 
interactions within each area interact with feedforward and feedback processes, at a laminar level. Our 
project aims to provide insights that will strongly advance understanding of fundamental aspects of cortical 
function—how neuronal populations communicate with each other and how that communication relates to 
cortical processing. We expect the understanding we gain, and the analytic and conceptual tools we 
develop, will be broadly applicable across different brain systems. Our ambitious goals will be 
accomplished by pooling complementary expertise of three PIs, building on a successful collaboration that 
has extended over many years.

## Key facts

- **NIH application ID:** 10914295
- **Project number:** 5R01EY035896-02
- **Recipient organization:** CARNEGIE-MELLON UNIVERSITY
- **Principal Investigator:** ADAM KOHN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $338,510
- **Award type:** 5
- **Project period:** 2023-09-01 → 2028-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10914295

## Citation

> US National Institutes of Health, RePORTER application 10914295, CRCNS: Dissecting Directed Interactions Amongst Multiple Neuronal Populations (5R01EY035896-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10914295. Licensed CC0.

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