Primary motor cortex neuronal discharge during reach-to-grasp: controlling the hand as a unit
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Updated: Sep 30, 2026

Assessing Corticospinal Excitability During Goal-Directed Reaching Behavior
Published on: December 2, 2022
C R Mason1, J E Gomez, T J Ebner
1Department of Neuroscience, University of Minnesota, 2001 Sixth St. S.E., Minneapolis, MN 55455, USA.
Abstract:
This study has begun to test the hypothesis that aspects of hand/object shape are represented in the discharge of primary motor cortex (M1) neurons. Two monkeys were trained in a visually cued reach-to-grasp task, in which object properties and grasp forces were systematically varied. Behavioral analyses show that the reach and grasp force production were constant across the objects. The discharge of M1 neurons was highly modulated during the reach and grasp. Multiple linear regressions models revealed that the M1 discharge was highly dependent on the object grasped, with object class, volume, orientation and grasp force as significant predictors. These findings are interpreted as evidence that the CNS controls the hand as a unit.
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