Retrieving accurate and distorted memories: Neuroimaging evidence for effects of emotion
Section snippets
Participants
Participants comprised 17 native English speaking Harvard undergraduate or graduate students. The data from one participant were excluded due to scanner malfunction. The remaining 16 young adults (8 women, 8 men) were ages 18–30. All were right-handed, native English speakers screened to exclude those with contra-indicators for MRI scanning, or with a history of depression. No participant was taking centrally-active medications. Informed consent was obtained from all participants in a manner
Behavioral data
ANOVA with response type (picture, no picture), item history (word-only, word–picture, new), and emotion type (emotional, neutral) as within-subject factors revealed a main effect of response type (F(1,15) = 21.1, P < 0.001, partial eta-squared = 0.59) as well as interactions between response type and item history (F(1,14) = 393., P < 0.001, partial eta-squared = 0.85) and among response type, item history, and emotion type (F(1,14) = 13.0, P < 0.001, partial eta-squared = 0.65). This three-way
Neuroimaging data
Random-effects analyses contrasted activation as a function of memory performance (comparing correct memory attributions and memory misattributions) separately for each emotion type (emotional or neutral) and item history type (from a word-only or word–picture trial; Table 1, Table 2, Table 3, Table 4). Because the goal of this study was to examine how the emotional content of the stimuli (regardless of their item histories) affected the neural processes that were associated with accurate
Discussion
The central aim of this study was to examine the processes that were related to accurate memory assignment for emotional and neutral items. The results suggest three principal conclusions. First, activity in regions implicated in prior studies of episodic retrieval (including a region of activity centered in the anterior hippocampus) corresponded with accurate retrieval regardless of the item's emotional content. Second, despite these commonalities, emotional content modulates the neural
Summary
By adopting a reality-monitoring paradigm that required participants to indicate which memories were attributable to external presentation, the present study could examine the processes engaged during correct memory attributions versus misattributions of emotional and neutral items. The results indicated that many of the regions found to correspond with retrieval of contextual details for neutral items (e.g., Dobbins et al., 2003, Giovanello et al., 2004, Wheeler and Buckner, 2003) also were
Acknowledgments
We thank Ronnie Bryan and Mariko Jameson for help with participant recruitment and testing. This research was supported by grants MH60941 (to D.L.S.) and MH070199 (to E.A.K.) from the National Institutes of Health and by a Massachusetts Biomedical Research Corporation Tosteson Postdoctoral Fellowship (to E.A.K.). Figures depicting the medial temporal-lobe regions reported in Table 1, Table 2, Table 3, Table 4 are available by contacting the first author.
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