Disrupting the Ventral Premotor Cortex Interferes with the Contribution of Action Observation to Use-dependent Plasticity

摘要

Action observation (AO), observing another individual performnan action, has been implicated in several higher cognitive processesnincluding forming basic motor memories. Previous worknhas shown that physical practice (PP) results in cortical motor representationalnchanges, referred to as use-dependent plasticityn(UDP), and that AO combined with PP potentiates UDP in bothnhealthy adults and stroke patients. In humans, AO results in activationnof the ventral premotor cortex (PMv), however, whether thisnPMv activation has a functional contribution to UDP is not known.nHere, we studied the effects disruption of PMv has on UDP whennsubjects performed PP combined with AO(PP+AO). Subjects participatednin two randomized crossover sessions measuring thenamount of UDP resulting from PP + AO while receiving disruptiven(1 Hz) TMS over the fMRI-activated PMv or over frontal cortexn(Sham). We found that, unlike the sham session, disruptive TMSnover PMv reduced the beneficial contribution of AO to UDP. To ensurenthat disruption of PMv was specifically interfering with the contributionnof AO and not PP, subjects completed two more controlnsessions where they performed only PP while receiving disruptivenTMS over PMv or frontal cortex. We found that the magnitude ofnUDP for both control sessions was similar to PP+AOwith TMS overnPMv. These findings suggest that the fMRI activation found in PMvnduring AO studies is functionally relevant to task performance, atnleast for the beneficial effects that AO exerts overmotor training.