事象関連電位による色の記憶探索過程に関する研究

The present study focused on memory search processes in nonverbal working memory. Event-related potentials (ERPs) were recorded while subjects engaged in two memory search tasks. Effects of memory set size on event-related potentials were compared between when memory sets consisted of one or four alphabets and when one to three unvocable color patches composed memory sets. In a letter search task, increase of memory set size caused the enlargement of negativities of ERPs between 250 and 450 ms latency range. Although the enhancement of negativities due to memory set size was also observed in a color search task, time course and scalp distribution of this effect were different from those in the letter search task. These results suggest that the nature of memory search process for nonverbal stimuli differs from those in verbal working memory.