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document
The aging motor system as a model for plastic changes of GABA-mediated intracortical inhibition and their behavioral relevance . Since GABAA-mediated intracortical inhibition has been shown to underlie plastic changes throughout the lifespan from development to aging , here , the aging motor system was used as a model to analyze the interdependence of plastic alterations within the inhibitory motorcortical network and level of behavioral performance . Double-pulse transcranial magnetic stimulation ( dpTMS ) was used to examine inhibition by means of short-interval intracortical inhibition ( SICI ) of the contralateral primary motor cortex in a sample of 64 healthy right-handed human subjects covering a wide range of the adult lifespan ( age range 20-88 years , mean 47.6 ± 20.7 , 34 female ) . SICI was evaluated during resting state and in an event-related condition during movement preparation in a visually triggered simple reaction time task . In a subgroup ( N = 23 ) , manual motor performance was tested with tasks of graded dexterous demand . Weak resting-state inhibition was associated with an overall lower manual motor performance . Better event-related modulation of inhibition correlated with better performance in more demanding tasks , in which fast alternating activation of cortical representations are necessary . Declining resting-state inhibition was associated with weakened event-related modulation of inhibition . Therefore , reduced resting-state inhibition might lead to a subsequent loss of modulatory capacity , possibly reflecting malfunctioning precision in GABAAergic neurotransmission ; the consequence is an inevitable decline in motor function .
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Intervention_Physical
Double-pulse transcranial magnetic stimulation ( dpTMS )
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Outcome_Physical
SICI
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Outcome_Physical
manual motor performance
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Outcome_Physical
Weak resting-state inhibition
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Outcome_Physical
Better event-related modulation of inhibition
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Outcome_Physical
Declining resting-state inhibition
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Outcome_Physical
reduced resting-state