Cognitive association formation in human memory revealed by spatiotemporalbrain imaging

Cognitive theory posits association by juxtaposition or by fusion. We emplo yed the measurement of event-related brain potentials (ERPs) to a concept f usion task in order to explore memory encoding of these two types of associ ations between word pairs, followed by a memory test for original pair orde r. Encoding processes were isolated by subtracting fusion task ERPs corresp onding to pairs later retrieved quickly from ERPs corresponding to pairs la ter retrieved slowly, separately for pairs fused successfully and unsuccess fully (i.e., juxtaposed). Analyses revealed that the encoding of these two types of associations yields different ERP voltage polarities, scalp topogr aphies, and brain sources extending over the entire time course of processi ng.