# Interhemispheric Communication and Compensation in Peripheral Nerve Injury

> **NIH NIH R01** · WASHINGTON UNIVERSITY · 2021 · $418,779

## Abstract

Use of the non-dominant left hand is critical for individuals who suffer chronic impairment of the dominant right
hand due to unilateral conditions such as peripheral nerve injury. (This project will study right-handed
individuals, and thus uses "right hand" instead of "dominant hand.") Most rehabilitation focuses on restoration
of function, but many patients never achieve this: 64,000 people per year in the USA have nerve injury to the
right hand but achieve satisfactory recovery, and these patients must learn to compensate by using the left
hand. However, the neural mechanisms of left hand compensation remain unknown. Our preliminary data
suggest that compensation involves interhemispheric mechanisms: the left hemisphere's mechanisms are
recruited to support the ipsilateral left hand. However, this mechanism has never been assessed with
neuroimaging during the left hand precision movements that would engage such a mechanism, nor in the
context of hand usage choices (left vs. right) during unconstrained reach-to-grasp action.
Our short-term goal is to identify interhemispheric mechanisms that support left hand compensation (both
performance and use), and determine whether the mechanisms arise from cortical asymmetry for movement
(hand dominance). This will provide the foundation for our long-term goal to develop and target therapies to
improve compensation for patients who face challenges to rehabilitation due to chronic right hand impairment.
Our patients will be individuals with chronic forced use of the left hand due to unilateral upper extremity
peripheral nerve injury. We will compare them with healthy patients in one fMRI study with 3 Aims:
 Aim 1: identify interhemispheric mechanisms that support left hand performance after right hand injury. We
 expect left hemisphere activity to correlate with left hand performance in fMRI, in patients > controls.
 Aim 2: identify interhemispheric mechanisms that support left hand usage after right hand injury. We expect
 left hemisphere activity to correlate with left hand usage outside fMRI, in patients > controls.
 Aim 3: determine whether the interhemispheric mechanisms arise from cortical asymmetry. We expect the
 mechanism to depend on hemisphere-specific specializations. Specifically, for patients who retain some
 function of their injured right hand, we expect that ipsilateral brain involvement will be demand-correlated
 during left hand action > during right hand action.
These findings will establish a mechanistic understanding of the interhemispheric cortical mechanisms of left
hand compensation. These mechanisms are the necessary foundation for future development of interventions
such as targeted neuromodulation, and precision-medicine prediction of which patients will benefit from
compensatory therapy. Moreover, our findings will establish a healthy-brain mechanism for the changes
following chronic forced use of the LH, which can serve as a baseline for future studies of central nervous
syst...

## Key facts

- **NIH application ID:** 10120280
- **Project number:** 1R01NS114046-01A1
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** Benjamin Allen Philip
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $418,779
- **Award type:** 1
- **Project period:** 2020-12-15 → 2025-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10120280

## Citation

> US National Institutes of Health, RePORTER application 10120280, Interhemispheric Communication and Compensation in Peripheral Nerve Injury (1R01NS114046-01A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10120280. Licensed CC0.

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