The amygdala's modulation of multiple stages of memory formation

New York University, New York NY

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Abstract

DESCRIPTION (provided by applicant): Emotion's interaction with episodic memory plays an important role in both adaptive function and psychopathology. Given this, understanding the range of means by which emotion can influence episodic memory is vital in efforts to develop treatments for psychological disorders. The goal of the proposed research is to characterize the behavioral and neural mechanisms of emotion's influence on episodic memory at multiple stages of memory formation. Episodic memory formation is not an all or none process. There are several distinct stages, each of which may be altered by emotion. The first stage is encoding and it has been suggested that emotion may influence encoding through its modulation of attentional processes (e.g. Anderson &Phelps, 2001;Easterbrook, 1959). After encoding is storage, which is thought to be an active process in that over time episodic memories can become more stable through consolidation. Retrieval assesses the effects of both encoding and consolidation. Studies examining memory retrieval have suggested that emotion not only enhances memory accuracy (McGaugh et al., 2000), but also might alter the characteristics of these memories (Ochsner, 2000). The reactivation of memories with retrieval may also change the quality of these memories (Anderson et al., 2004;Dudai &Eisenberg, 2004). Following retrieval, memory is once again stored, and this additional storage, called reconsolidation, could also be modulated by emotion. The effects of reactivation and reconsolidation on memory can be assessed by a second retrieval, or re-retrieval. The primary neural mechanism that has been proposed for emotion's influence on episodic memory is the amygdala's modulation of hippocampal consolidation with arousal, specifically as it effects subsequent memory accuracy (see Phelps, 2004 for a review). Although understanding this aspect of emotional memory formation is important, it only captures a subset of emotion's overall influence on episodic memory in humans. The aim of the current proposed research is to explore the behavioral characteristics and neural systems underlying emotion's effect on episodic memory formation at encoding, retrieval, and re-retrieval. At each stage it is proposed the amygdala may play a critical role through its influence on hippocampal and parahippocampal function. There are three specific aims: Specific Aim 1 is to further specify how emotion influences attention and perception, and examine how this might affect the neural systems of memory encoding. Specific Aim 2 is to characterize emotion's impact on the behavioral and neural mechanisms of memory retrieval over time, specifically how emotion might alter factors related to recollection and familiarity. Specific Aim 3 is to explore if emotion has an impact on the re-retrieval of memories, with a goal of determining if the reactivation and reconsolidation of memory is influenced by emotion.