Age-related changes in short-interval intracortical facilitation and dexterity

Abstract

Functional changes in the primary motor cortex might contribute to the age-related decline infine motor control. We measured short-interval intracortical facilitation (SICF) in an intrinsichand muscle with paired-pulse transcranial magnetic stimulation at interstimulus intervals(ISIs) of 1.5, 2.5, and 4.5 ms in young and old subjects and examined its association withdexterity. We found age-related effects in SICF, with greater facilitation in old than youngsubjects at the 1.5-ms ISI and greater facilitation in young than old subjects at the 2.5-ms ISI.SICF at the 2.5-ms ISI was positively correlated with performance on a task that requiredcoordinated and dextrous use of both hands, suggesting that this measure indicates a capacityfor executing demanding manual tasks.