Cortical changes in motor preparation facilitate changes in motor execution following an intervention in severe chronic hemiparetic stroke

Abstract

ObjectiveEffective interventions have demonstrated the ability to improve motor function by reengaging ipsilesional resources, which has been shown to be critical and feasible for hand function recovery even in individuals with severe chronic stroke. However, the question remains how these focal activity changes (i.e., changes in activity within motor regions) relate to altered cortico-cortico interactions within/across multiple regions. MethodsEight individuals with severe chronic stroke participated in a device-assisted intervention. Pre- and post-intervention, we collected EEG while performing hand opening with/without lifting the paretic arm. We quantified changes in focal cortical activity at movement execution and connectivity during movement preparation. ResultsPost-intervention, individuals displayed a reduction in coupling from ipsilesional M1 to contralesional M1 within gamma frequencies during movement preparation for hand opening. This was followed by a reduction in activity in contralesional primary sensorimotor cortex during movement execution. Meanwhile, during lifting and opening, a more inhibitory coupling within ipsilesional M1 from gamma to beta frequencies was accompanied by an increase in ipsilesional primary sensorimotor cortex activity. ConclusionsChanges in coupling within or between motor regions during movement preparation complement topographical activity changes at movement execution. SignificanceOur results suggest that changes in cortico-cortico interactions may lead to corresponding changes in focal cortical activity.