Age-related decline in the responsiveness of motor cortex to plastic forces reverses with levodopa or cerebellar stimulation

• Published in: Neurobiology of aging Vol. 35; no. 11; pp. 2541 - 2551
• Main Authors: Kishore, Asha, Popa, Traian, James, Praveen, Yahia-Cherif, Lydia, Backer, Febina, Varughese Chacko, Lijo, Govind, Preetha, Pradeep, Salini, Meunier, Sabine
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.11.2014
• Subjects: Adult; Aged; Aging; Aging - physiology; Cerebellum; Cerebellum - physiology; Dopamine - physiology; Evoked Potentials - physiology; Female; Humans; Internal Medicine; Levodopa; Levodopa - pharmacology; Male; Middle Aged; Motor cortex; Motor Cortex - physiology; Motor Cortex - physiopathology; Motor Skills; Neurology; Neuronal Plasticity - physiology; Plasticity; Psychomotor Performance; Synaptic Transmission - drug effects; Transcranial Direct Current Stimulation; Young Adult; Cerebellum; Aging; Levodopa; Motor cortex; Plasticity
• ISSN: 0197-4580; 1558-1497
• DOI: 10.1016/j.neurobiolaging.2014.05.004

Abstract The plasticity of motor cortex is integral for motor memory and skills acquisition but it declines with aging. Forty healthy volunteers, across 6 decades, were tested to examine the (a) age-dependency of motor cortex responsiveness to plasticity induction, as measured from the response to paired associative stimulation (PAS) and the (b) effect of aging on the cerebellar modulation of motor cortex response to PAS. We examined if reduced dopaminergic transmission was involved in the age-related decline of response to PAS by retesting 10 of the older subjects after a single dose of levodopa. There was a substantial decline in the motor cortex response to PAS with aging, which was restored by levodopa in the older subjects. The cerebellar modulation of motor cortex response to PAS was less vulnerable to aging and a single session of cerebellar inhibition reinstated the cortical responsiveness in older subjects. Both levodopa and cerebellar inhibition can be tested for their ability to enhance motor skills acquisition and motor performance in the elderly individuals.