Modulation of episodic memory encoding by emotional stimulation in fMRI

NemoImage

13, Number

6, 2001,

Part 2 of 2 Parts ID

E al@

EMOTION

Modulation

& COGNITION

of episodic memory encoding by emotional stimulation

in fMR1

Susanne Erk*, Markus Kiefer*, Jo Grothe*, Arthur P. Wunderlicht, Manfred Spitzer*, Henrik Walter*+ *Department of Psychiatry, University of Ulm, Ulm, Germany tDepartment

of Diagnostic Radiology, University of Ulm, Ulm, Germany [email protected]

introduction Emotions do modulate cognitive processes, e.g. memory. Here we present a new paradigm for event related fMR1 with which it is possible to study the interaction of emotion and cognition. Based on theories in affective neuroscience, we hypothesized that (i) positive emotions would enhance free recall compared to negative emotions (1) and (ii) that brain activity in certain brain regions would predict recall of verbally encoded material (2) depending on the valence of emotional stimulation. Methods In an event-related design, 11 healthy subjects (7 male) were shown positive, negative or neutral pictures from the International Affective Picture System (IAPS). Briefly after presenting the picture for 3000 ms a neutral word was shown, which had to be classified as abstract or concrete. Pictures were presented blockwise sorted by emotions (7 events/valence) to ensure a reliable level of specific emotional stimulation. The experiment consisted of two sessions with 42 events each. After each session, subjects were asked to freely recall the words they have seen during the preceding session. jiVfRZ-protocol: Siemens Magnetom Symphony scanner, single-shot EPI sequence, TE/TR of 50/2500 ms, 21 slices covering the whole brain, two sessions with 209 volumes each. Data preprocessing and analysis was done using Statistical Parametric Mapping (SPM, Wellcome Institute of Cognitive Neurology, London). Results Behavioral results: Subjects remembered significantly more words following positive pictures than words following negative (p=.OO2) or neutral (p=.OOl) pictures. imaging resulrs: Here we report only contrasts asking which regions were more active during the stimulation period when this period contained words that were recalled compared to periods containing words not recalled (p<.OOl). There was one common region found for positive as well as negative conditions, namely the left inferior frontal region (BA 47). For the positive conditions further regions found were the right lingual gyrus and a region encompassing the right parahippocampal and fusiform gyms. For the negative condition additional regions found were the right inferior frontal cortex (BA 47). the left ventromedial cortex (BA 11), left DLPFC (BA 9) and left inferior parietal cortex; at a lower threshold (pc.01) we found additionally left and right amygdala and hippocampus. Conclusion Encoding verbal material under positive emotional stimulation enhances free recall which is in line with the dual force approach of Fiedler (1). Furthermore, we were able to replicate results by Wagner et al. (2) showing that activity in the inferior frontal cortex and the parahippocampal/fusiform region does predict remembering and forgetting of verbal material. Most notably, we found that brain regions predicting recall differed in respect to emotional stimulation, i.e. that succesful encoding is modulated by emotion. References (1) Fiedler K in Forgas JP: Emotion and social judgement. (2) Wagner AD et al.: Building Memories: Remembering Science, 281: 1188-91, 1998.

Oxford, 1991, pp. 82-104. and Forgetting of Verbal Experiences

s395

as Predicted

by Brain

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