# ROLE OF MODULAR INHIBITORY NETWORK IN MOUSE VISUAL CORTEX

> **NIH NIH R01** · WASHINGTON UNIVERSITY · 2020 · $381,250

## Abstract

ABSTRACT
In this proposal we are directing attention to L1, the target of higher thalamocortical connections, cortical
feedback and site of input to apical dendrites of pyramidal cells (Pyr). Inputs to L1 were considered to be
diffuse and non-specific until we have shown that inputs to L1 of mouse V1 are clustered55. The clustering
challenged the notion that rodent visual cortex is non-columnar93 and revealed a mesoscale architecture which
is preserved in primate cortex55. We have recently found a similar spatial clustering of neuropil and somata of
GABAergic neurons (INT). The modularity involves PV- (parvalbumin), SOM- (somatostatin) and VIP-
(vasoactive intestinal peptide) expressing cells. The clustering of INT contrasts with the uniformity envisioned
by the canonical circuit model25, and suggests module-specific motifs for counterbalancing excitation with
inhibition. The periodicity of INT-rich and INT-poor clusters interdigitates with thalamocortical and cortical long-
range connections to L1, where they synapse with INT in source-specific fashion. The clustering of INT
suggests a non-uninform distribution of inhibition across V1, which differs from previous proposals143. INT
clusters resemble patches of Pyr cells with different spatiotemporal senitivities55. Preliminary results suggest
that neurons with high temporal acuity are preferentially localized in INT-rich interpatches, whereas neurons
with high spatial acuity reside in INT-poor patches. The overlap of high temporal acuity with INT-rich modules
raises several important questions, whether: inhibition in these modules is stronger, feedforward inhibition
mediated by PVs is responsible for it, the more strongly inhibited Pyr cells project to specific targets, and
whether PVs play a role in the diverse spatiotemporal visual preferences in patches and interpatches. INT-rich
and INT-poor modules do not exist in isolation. Only INT-poor patches receive input from the lateral geniculate
nucleus and feedback from the higher visual areas, LM, AL and RL, whereas input from the lateral posterior
thalamus (LP) and top-down projections to INT-rich interpatches originate from dorsal stream areas136, PM and
AM. Thus, INT-rich interpatches are preferentially connected to dorsal stream areas and the LP, from where
they receive attention and locomotion-related inputs used for spatial navigation and detection of unexpected
motion incongruent with the running speed104,109,124. Previous studies2,70 have shown that suppressive top-down
signals from the stimulus surround are mediated through SOM neurons, whereas top-down signals are
mediated via VIP-cell-mediated disinhibition34,147. This suggests that top-down information for object
segmentation and visually guided actions may differentially involve INT-rich and INT-poor modules. To test
these hypotheses we propose to determine whether: 1) the distribution of PV, SOM and VIP neurons in V1 is
modular, 2) the strength of PV-, SOM- and VIP-mediated inhibitio...

## Key facts

- **NIH application ID:** 9942453
- **Project number:** 5R01EY027383-04
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** ANDREAS Hans BURKHALTER
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $381,250
- **Award type:** 5
- **Project period:** 2017-09-01 → 2022-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9942453

## Citation

> US National Institutes of Health, RePORTER application 9942453, ROLE OF MODULAR INHIBITORY NETWORK IN MOUSE VISUAL CORTEX (5R01EY027383-04). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/9942453. Licensed CC0.

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