Conjunction analysis of cortical activations common to encoding and retrieval

The notion of overlap between encoding and retrieval processes is central i n cognitive theories of episodic memory, but to date most functional neuroi maging studies have emphasized differences between these processes. In the present study, overlap between encoding and retrieval processes was investi gated by analyzing data from a positron emission tomography (PET) study of encoding and retrieval of different kinds of event information. Using a con junction analysis, we specifically aimed at identifying overlap in activati on patterns for encoding and retrieval of three classes of event informatio n: item, temporal, and spatial. It was found that both encoding and retriev al of spatial information activated posterior parietal areas bilaterally. I n addition, item encoding and retrieval were associated with increased acti vity in the right temporal pole, and temporal encoding and retrieval with l eft inferior frontal and left inferior temporal regions. These findings sug gest that when specific episodic information is retrieved from memory, regi ons involved in encoding of the same information are engaged. Microsc. Res. Tech. 51: 39-44, 2000. (C) 2000 Wiley-Liss, Inc.