不同形式运动锻炼老年人运动皮层突触可塑性的差异：来自TMS的研究证据

lthough studies have found that exercise can lead to changes in the plasticity of the motor cortex, little is known about the changes in primary motor cortex synaptic plasticity associated with different forms of exercise among older adults. The purpose of this study was to compare the differences in motor cortex synaptic plasticity associated with a small hand muscle among older adults who regularly participated in table tennis or tai chi or who were sedentary.Based on inclusion/exclusion criteria and their answers to a self-reported questionnaire, 54 older adults (60~70 years) were selected who often participated in table tennis (n = 18) or tai chi (n = 18) exercise or who were sedentary (n = 18). The target muscle was the abductor pollicis brevis of the right hand. Motor cortex synaptic plasticity associated with the abductor pollicis brevis muscle was induced by a paired combination of peripheral nerve electrical stimulation and transcranial magnetic stimulation with an interval of 25 ms (PAS25). Single-pulse and double-pulse transcranial magnetic stimulation was applied to the left primary motor cortex to measure changes in motor evoked potentials (MEPs) and short-interval intracortical inhibition recorded in the abductor pollicis brevis muscle before and after PAS25, to compare the differences in primary motor cortex synaptic plasticity among the three groups.The results showed that mean MEP amplitudes immediately and 30 and 60 min after PAS25 in the table tennis group were significantly higher than those in sedentary group; mean MEP amplitudes immediately and 30 min after PAS25 in the tai chi group were significantly higher than those in the sedentary group; and mean MEP amplitudes immediately and 30 and 60 min after PAS25 in the table tennis group were significantly higher than those in the tai chi group. There were no differences in the short-interval intracortical inhibition at any time point after PAS25 among the three groups.These results indicated that regular participation in table tennis or tai chi can induce a sustained increase in primary motor cortex excitability in older adults and that there are differences in primary motor cortex synaptic plasticity in older adults associated with different forms of exercise. These results suggest that increased synaptic plasticity in the motor cortex may play an important role in the acquisition and promotion of motor skills during exercise in older adults.