Recapitulation of emotional source context during memory retrieval

Abstract

Recapitulation involves the reactivation of cognitive and neural encoding processes at retrieval. In the current study, we investigated the effects of emotional valence on recapitulation processes. Participants encoded neutral words presented on a background face or scene that was negative, positive or neutral. During retrieval, studied and novel neutral words were presented alone (i.e., without the scene or face) and participants were asked to make a remember, know or new judgment. Both the encoding and retrieval tasks were completed in the fMRI scanner. Conjunction analyses were used to reveal the overlap between encoding and retrieval processing. These results revealed that, compared to positive or neutral contexts, words that were recollected and previously encoded in a negative context showed greater encoding-to-retrieval overlap, including in the ventral visual stream and amygdala. Interestingly, the visual stream recapitulation was not enhanced within regions that specifically process faces or scenes but rather extended broadly throughout visual cortices. These findings elucidate how memories for negative events can feel more vivid or detailed than positive or neutral memories.

Keywords: Emotion; Memory; Reactivation; Recapitulation; Source memory.

Figure 1

Schematic of the encoding and retrieval task. During the encoding task, participants were asked to remember the word for the upcoming memory test and to make a decision, via button press, as to whether the image was a face or scene. During retrieval, participants were asked to make a remember (R), know (K) or new (N) judgment for each word.

Figure 2

Behavioral performance, N = 19. Neg = negative; Pos = positive; Neu = neutral; FA = false alarm rate. Hit rates were higher for words encoded with negative scenes compared to positive and neutral scenes, but hit rates for words encoded with negative, positive or neutral faces did not statistically differ.

Figure 3

Encoding-to-retrieval spatial overlap for Remember Hits > Know Hits at each level of valence. Red = Negative; Positive = Blue; Neutral = Green. Coronal slice at MNI Y = −6 showing recapitulation in the amygdala associated with negative but not positive or neutral context

Figure 4

Encoding-to-retrieval spatial overlap for Remember Hits> Misses at each level of valence. Red = Negative; Positive = Blue; Neutral = Green.

Figure 5

Encoding-to-retrieval overlap for Face Remember Hit> Face Know/New showing reactivation in left FFA in cyan. Encoding-to-retrieval overlap for Scene Remember Hit> Face Know/New showing reactivation in bilateral PPA in yellow. Slices at MNI Z = −20, −15, −10, −5.

Figure 6

Encoding-to-retrieval overlap that was exclusive to successful memory for negative faces compared to positive scenes, suggesting that recapitulation effects are more associated with valence than arousal. There was no above-threshold activity for the reverse analysis of positive scenes > negative faces.

Figure 7

Encoding-to-retrieval overlap that was exclusive to successful memory for negative faces compared to positive faces. These comparisons indicate that effects of negative valence cannot be easily be accounted for by differences in visual properties of the stimulus category. Negative and positive face stimuli used in the current study were perceptually very similar (re: NimStim Set of Facial Expressions; Tottenham et al., 2009).