Primary motor cortical neurons reflect visuomotor coordination during arm-reaching movements

摘要

Primary motor cortical neurons reflect visuomotor coordination during arm-reaching movements A primary motor cortex (M1) is known to limitedly reflect on a disposition of a visuomotor coordination (VC), so-called visual- motor integration, during movements unlike cerebellum which influences on spatial orientation in an aspect of the visuomotor adaptation. In this study, we thus investigate neuronal properties associated with the VC from the M1 during the two types of arm movement tasks which arm reaches to the fixed or slowly drifting target. For this exploration, we utilized the M1 activities acquired from a rhesus macaque which performs the reaching task accord- ing to the randomly located target by a stimulation robotic arm in three-dimensional spaces. To figure out neuromechanical dif- ference between the tasks, we first confirmed the peristimulus time histogram (PSTH) of individual neurons, and then, yielded the low-dimensional manifold representing a neuronal population. Plus, we performed the identical analysis using each neuronal sub- set which is clustered by the trough-to-peak ratio of the averaged action potential corresponding to each neuronal spike. Through these progresses, we could confirm that firing activities of spe- cific neurons change according to the speed of the drifting target. Also, the principal components revealed significantly difference between target stimulus given periods before reaching onset in the tasks. In conclusion, the M1 is likely to contain information cod- ing VC simultaneous with reaching task. That suggests evidences of particular cognitive process associated with inferring the desti- nation according to tracking the target.