Arm-use dependent lateralization of gamma and beta oscillations in primate medial motor areas.

The neurons in the motor cortex show lateralization depending on the arm to use. To investigate if local field potential (LFP) oscillations change with contralateral and ipsilateral arm use, we analyzed the power of LFP in supplementary motor areas (SMA) and pre-SMA while animals performed a delayed-response arm use task under visual guidance and memory-based. LFP power changed with the laterality of the arm use, but it was frequency dependent. Specifically, power in the gamma range increased during contralateral arm use, while beta power increased with ipsilateral arm use. Subsequently, we confirmed that the frequency-dependent laterality was true also for the memory-driven movements. Our data therefore suggest that gamma oscillation is linked to the local neuronal activities in the contralateral hemisphere, and beta oscillation is related to withholding undesired arm movements by suppression of the local neuronal activities of the ipsilateral hemisphere.