The Role of Recollection, Familiarity, and the Hippocampus in Episodic and Working Memory

The hippocampus plays an essential role in long-term episodic memory by supporting the recollection of contextual details, whereas surrounding regions such as the perirhinal cortex support familiarity- based recognition discriminations. Working memory - the ability to maintain information over very brief periods of time - is traditionally thought to rely heavily on frontoparietal attention networks, but recent work has shown that it can also rely on the hippocampus. However, the conditions in which the hippocampus becomes involved in working memory are unclear and whether it contributes to recollection or familiarity-based responses in working memory is only beginning to be explored. In the current paper, we first review and contrast the existing amnesia literature examining recollection and familiarity in episodic and working memory. The results indicate that, in contrast to episodic memory, in working memory the hippocampus is particularly critical for familiarity-based rather than recollection-based discrimination. Moreover, they indicate that the role of the hippocampus in working memory can be obscured due to ‘criterion-induced process-masking’ because it primarily supports intermediate-confidence recognition decisions. We then report results from a new working memory study examining the ability of amnesics to detect global and local changes in complex objects, which indicates that the hippocampus plays an especially critical role when working memory relies on the detection of global rather than discrete changes. We conclude by considering the results in light of neurocomputational models and proposing a general framework for understanding the relationship between episodic and working memory.