Figure 7.

Somatotopy of SICF_SAI interaction

Hetero- and homotopic interactions and somatotopic specificity were tested with EMG recorded from the FDI and APB muscles (target muscle indicated in bold and underlined). Similar levels of SAI (grey), SICF (black) and SICF_SAI (white) were observed for all interactions tested. The conditions tested were: homotopic interaction: median nerve stimulation with APB as target muscle (A); homotopic interaction: ulnar nerve stimulation with FDI as target muscle (B); heterotopic interaction: median nerve stimulation with FDI as target muscle (C). SICF was significantly facilitated in the presence of SAI with unadjusted (not shown) and adjusted TS and to similar degrees for both the homotopic and heterotopic muscles. This is confirmed by linear mixed model analysis which showed no significant effect of muscle or muscle × condition interaction. Asterisks indicate significant difference in SAI and SICF relative to TS baseline (*P < 0.05, **P < 0.01).