Fig. 3.

Threshold-tracking values obtained from each paired-pulse protocol. A: short-interval intracortical inhibition (SICI) at 1 ms was reduced in older adults compared with young in both TMS sessions. No differences in SICI at 3 ms (B), long-interval intracortical inhibition (C), or late cortical disinhibition (D) were observed between young and older adults in either session. In A–C, greater inhibition is indicated upward. In D, greater disinhibition is indicated downward. Data are presented as means + SE. N = 15 young and 15 older adults.