Ipsilateral silent period: A specific marker of transcallosal motor transfer?

Objective: The ipsilateral silent period (iSP) is supposed to be a specific marker of transcallosal motor inhibition. The aim of the present study was to re-evaluate whether the iSP is a pure marker of transcallosal motor inhibition or if it rather represents the function of multiple motor fibre tracts. Methods: Experiment 1: ISP measurements (onset, duration, depth) were performed in the first dorsal interosseous (FDI) and abductor pollicis brevis (APB) muscles of 20 healthy subjects by focal transcranial magnetic stimulation of one primary motor cortex during maximal contraction of the ipsilateral target muscl…