The Effect Of Different Memory Loads On Event-related Potential N270

Objective:To characterize the changes of N270 in healthy volunteers under the condition of different memory loads . Method:Forty healthy volunteers from different university received the examination of ERP.A Sternberg paradigm modified was applied during the examination, all subjects were demanded to press left or right button as quickly as possible while stimulus materil which were a serial of digit figures were randomly presented in the center of screen. They were divided into different three levels in memory load accoding to the content required memorize.Whether the two digits compared were identical, we looked them as match condition ; Whether the two digits compared were different, we looked them as mismatch condition. Both conditions in three memory load were of equal probaibility. Result:Under the mismatch condition, N270 could be elicited.The mean amplitudes of N270 elicited by high memory load were significantly lower than those by middle memory load and low memory load. The mean amplitudes of N270 elicited by middle memory load were also lower than those by low memory load, however, which did not obtain significance in stastistics. Conclusion:In working memory tasks, the more memory load was, the more neural resourse would be occupied, as neural resourse was a basis to produce electrical activities, it was displayed lower mean amplitudes in N270.