Human motor fatigability as evoked by repetitive movements results from a gradual breakdown of surround inhibition.

ABSTRACT: Motor fatigability emerges when demanding tasks are executed over an extended period of time. Here, we used repetitive low-force movements that cause a gradual reduction in movement speed (or 'motor slowing') to study the central component of fatigability in healthy adults. We show that motor slowing is associated with a gradual increase of net excitability in the motor network and, specifically, in primary motor cortex (M1), which results from overall disinhibition. Importantly, we link performance decrements to a breakdown of surround inhibition in M1, which is associated with high coactivation of antagonistic muscle groups. This is consistent with the model that a loss of inhibitory control might broaden the tuning of population vectors such that movement patterns become more variable,

SUBMITTER: Bachinger M 

PROVIDER: S-EPMC6746551 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature