Towards a neurobiology of "oromanual" motor control: behavioral analysis and neural mechanisms

Northwestern University At Chicago, Evanston IL

Investigators

Abstract

PROJECT SUMMARY The goal of this proposal is to develop new methods to study the neurobiology of “oromanual” motor control – goal-directed, coordinated movements of jaw- and hand-related structures, as exemplified by food-handling behavior, a natural and ethologically essential activity. Movements of the hands and jaw have traditionally been studied entirely separately – e.g. actions such as reach-to-grasp and mastication, respectively. Yet many mammals, especially primates and rodents, use coordinated hand-and-jaw movements for natural behaviors, particularly food handling. Neither the precise kinematics of coordinated hand-jaw movements nor the underlying neural mechanisms are well understood. Here we propose a research program that will begin to address this gap in knowledge through a series of exploratory activities. During oromanual food-handling, electromyography methods will be used to concurrently record masseter and forelimb activity, together with machine learning- assisted tracking of movements captured by kilohertz video. Both head-fixed and freely moving paradigms will be developed, to enable implementation of electrophysiological and optical recordings of neural activity across motor/frontal cortical areas during food-handling. Cortical activity will be analyzed in relation to distinct behavioral modes and sub-movements, and inform how active units contribute as a population to the overall cortical activity pattern and hand-jaw interactions. Circuit-mapping paradigms will be developed to dissect the circuits mediating communication along masseter- and/or forelimb-related corticobulbar pathways impinging on masseter motor neurons in the motor trigeminal nucleus. The overall outcome will be a novel suite of tools, experimental paradigms, and conceptual framework to enable future in-depth investigation of oromanual motor control.