Short-interval intracortical inhibition to the triceps brachii during arm cycling

Abstract

Non-human animal work shows the existence of a network of spinal cells called central pattern generators (CPGs) that partially control locomotion. Indirect evidence shows that CPGs also contribute to human locomotion. However, humans require the integration of descending input from cortical motor-related areas for the generation and control of locomotive outputs. Unfortunately, the cortical circuits that modulate the excitability of the motor cortex during locomotor outputs are not well understood. Short-interval intracortical inhibition (SICI) is one circuit thought to help inhibit the motor cortex. The majority of work done to understand SICI has utilized isometric contractions, but evidence suggests that cortical circuits are modulated differently during locomotor outputs. Our lab has shown the presence of SICI to the biceps brachii during arm cycling, but did not investigate SICI to the triceps brachii, another vital muscle required for arm cycling. Examining SICI to the triceps may improve knowledge translation to neurological rehabilitation programs that utilize arm cycling.