# Towards elucidation of circuit mechanisms for feeding-related manual dexterity

> **NIH NIH R21** · NORTHWESTERN UNIVERSITY · 2020 · $434,500

## Abstract

PROJECT SUMMARY
Dexterous food-handling is a critical but still poorly understood type of basic motor behavior. We propose an
exploratory research program to investigate how the mouse uses its digits and forepaws to dexterously handle
food. Preliminary results suggest that mouse food-handling movements, despite appearing extremely complex,
can be decomposed into several types of simpler elements, tentatively identified as distinct and very rapid
submovements that exhibit partly stereotyped and partly variable kinematic features. They also suggest that the
mouse’s thumb (first digit, or D1; pollex) plays a surprisingly large and previously unrecognized role in dexterous
food-handling. To explore these hypotheses and observations, we will first develop an approach for quantitatively
characterizing seed-handling behaviors of freely moving mice. For this we will use high-speed, close-up video
capture, combined with deep neural network methods for automated markerless tracking (DeepLabCut). We will
then develop a novel trial-based paradigm for characterizing seed-handling under the more experimentally
controlled conditions of head-fixation. We will combine this approach with tools for optogenetic silencing of either
selectively targeted cortical areas or selectively labeled corticospinal neurons in motor cortex, as well as multi-
probe/multi-channel linear array recordings of spiking activity in key nodes along sensorimotor pathways.
Collectively this work will advance our understanding of the elemental movements involved in the dexterous
manipulation of food, providing new insights into this process in a genetically tractable model organism, and
opening the way for future studies to dissect the cellular mechanisms in sensorimotor circuits mediating specific
aspects of forelimb and digit motor control.

## Key facts

- **NIH application ID:** 9982480
- **Project number:** 1R21NS116886-01
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **Principal Investigator:** Gordon M Shepherd
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $434,500
- **Award type:** 1
- **Project period:** 2020-04-01 → 2022-09-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9982480

## Citation

> US National Institutes of Health, RePORTER application 9982480, Towards elucidation of circuit mechanisms for feeding-related manual dexterity (1R21NS116886-01). Retrieved via AI Analytics 2026-06-12 from https://api.ai-analytics.org/grant/nih/9982480. Licensed CC0.

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