ID 277 – The effects of BDNF Val66Met polymorphism on motor learning studied electrophysiologically by sensory-motor integration

Objective We previously found by performing sensory-motor integration (SMI) studies on sedentary subjects that there were less short latency afferent inhibition and higher facilitation after basketball shooting exercises which partially subsided after exercising for five days. We herein present the effect of brain-derived neurotrophic factor (BDNF) val66met polymorphisms on this motor learning process. Method Two groups of healthy sedentary subjects [16 Val66Val (group I); 10 Val66Met and 1 Met66Met (group 2)] performed standardized 5-day basketball shooting exercises under supervision. SMI studies were done before and after the exercise on day 1 (T0, T1) and after the exercise on day 5 (T2). SMI was studied by electrical median nerve stimulation at the wrist followed by transcranial magnetic stimulation (TMS) of the contralateral motor cortex. Recordings were made from thenar and flexor carpi radialis (FCR) muscles. Inter-stimulus intervals between the electrical stimulus and TMS were 20, 35, 50, 65, 80, 100 and 200 ms. Results Group 2 had significantly more reduced short afferent inhibition and increased facilitation at T2. Conclusion In group 2, persistently increased excitability in the sensory-motor cortex on day five might be the reflection of a defect in changing the learning process into a different mechanism.