Research On Brain Function Localization Of Motor Memory Chunks:a RTMS Study

Most of the complex motor actions that people perform in everyday life consist of series of relatively simple movements. As studies had proven that with practice, the order of movements if learned and people’s action spontaneously become a sequence of successive and stabilized motor chunk, in the meanwhile the action get faster and more precise gradually. Over the last decades, ample research had been devoted to unraveling neural mechanisms underlying sequential motor skill. So continuing to locate the brain regions related with sequential motor skill and discriminating their functions respectively will enrich neural theoretical foundations and give instructions on motor learning and rehabilitation treatment.Based on previous study, from perspective of behavioral science and cognitive neuroscience, present study aims to find the function of SMA and pre-SMA on sequence task by using rTMSand dual processor model. Result shows that the subjects can only discrete 6 keys into 3-3 motor chunks instead of 2-2-2 motor chunks. Even few of them performed 2-2-2 motor chunks, this performance is not sustained in following tests. In addition, the advance on inter-chunk is better than advance on intra-chunk. After SMA process, executing the whole sequence become slowly, but after pre-SMA process, only when execute the beginning of the second chunk become slowly.In conclusion, firstly, people could just learn 3-3 chunks according to the guidance in sequence task. Secondly, during the sequence task with moderate practice, pre-SMA as the cognitive processor in dual processor model, response for the chunking selection. Lastly, SMA, as the motor processor, also takes part in the moderate practice sequence task and response for the chunking execution.