Interhemispheric Inhibition Predicts the Magnitude of Mirror Movements in Healthy Subjects

It has been proposed that interhemispheric inhibition mediated through the corpus callosum is important to prevent mirror movements (MM) during intended unimanual finger movements. To test this, we correlated interhemispheric inhibition (IHI) with the magnitude of MM in 12 healthy volunteers (age, 21–40 years). MM were quantified according to an established protocol (Mayston et al. Ann Neurol 1999; 45: 583). Subjects were instructed to perform 50 ballistic index finger abductions with one hand (task hand) at a self-paced rate of about 0.2Hz whilst maintaining an isometric contraction with the first dorsal intero…