A TMS-induced cortical silent period delays the contralateral limb for bimanual symmetrical movements and the reaction time delay is reduced on startle trials

Abstract

Bilateral responses are typically planned synchronously and performed symmetrically. Here, we show that delaying the initiation of one limb using transcranial magnetic stimulation (TMS) to produce a cortical silent period does not impact the other limb during bimanual movements. Also, the TMS-induced delay is reduced when a startling acoustic stimulus (SAS) triggers the movement. These results confirm that tightly coupled bilateral responses can be dissociated by contralateral TMS- and SAS-triggered responses involve greater reticulospinal output.