Conclusion

In conclusion, the present experiment utilized different reaction time tasks, which involved distinct preparation and inhibition processing requirements to examine the timing and magnitude of suppression of corticospinal excitability just prior to the go‐signal. No differences were evident in the MEP amplitude at the warning signal, which then showed similar suppression for all three RT tasks until 150 ms prior to the go‐signal. During the final 150 ms, the magnitude of suppression diverged between the tasks, as the choice RT resulted in no further suppression compared to the simple and go/no‐go RT tasks, which exhibited decreased MEP amplitude until the go‐signal. Collectively, these results indicate that the nature and origin of the suppression is likely multifactorial, with early (300 to 150 ms prior to the go‐signal) corticospinal excitability suppression potentially functioning to improve signal detection/initiation processes, and later (within 150 ms of the go‐signal) suppression relating to preparatory state optimization and/or inhibitory processes to prevent early or unwanted responses. Thus, changes in corticospinal excitability may be an inherent feature of processes associated with both motor preparation and initiation, and the timeline and magnitude of suppression depend on the nature of the task being executed.