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Abstract:
Event-related potentials (ERPs) were used to investigate
mood-congruent processes during memory encoding and their relation
to recall performance. It was tested whether affective words elicit
differential brain activation depending on valence, mood and
encoding task. Subjects in positive or negative mood were presented
with adjectives of positive and negative valence (e.g., friendly,
angry). In one condition, words were complete. In the other
condition, words had to be generated from fragments. Mood states
were induced by showing movies. Mood congruent word recall was
largest in positive mood and in the generate condition. Comparably,
mood-dependent ERP effects were observed on the N400 ERP component,
an electrophysiological index for semantic processing and
integration. In positive mood, negative words elicited a more
negative N400 than positive words at central and parietal
electrodes, particularly in the generate condition. In negative
mood, a similar valence effect was obtained at parietal electrodes,
but disappeared at left central electrodes. The results suggest
that mood-congruency effects already emerge during encoding. For
positive mood states congruent words are more easily integrated
into a memory trace than incongruent words, particularly during
elaborative encoding. Negative mood does not entirely reverse this
activation pattern in the cortical network involved in N400
generation. It rather reduces the general preference for positive
valence.
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