Examining the N400m in affectively negative sentences: A magnetoencephalography study.

Magnetoencephalography was used to examine the effect on the N400m of reading words that create emotional violations in sentences. The beginnings of the sentences were affectively negative and were completed with either a negative congruous, positive incongruous, or neutral incongruous adjective (e.g., "My mother was killed and I felt bad/great/normal"). The task conditions were also manipulated to favor semantic over affective processing. Compared to the sentences with the congruous negative adjectives, the results of sensor space analysis showed that there was an N400m effect with the sentences with the neutral but not positive adjectives, despite both types of sentences containing an emotional violation. Source localization results showed a similar pattern where the sentences with the incongruous positive versus congruous negative adjectives showed no significant N400m effect in the temporal and frontal areas examined, but the sentences with the incongruous neutral versus incongruous positive adjectives in the temporal areas did, particularly the left middle temporal gyrus. These results suggest that (a) the N400m effect was likely to be caused by the incongruous neutral adjectives being comparatively harder to integrate into a negative emotional context than the incongruous positive ones, (b) emotional context created by the negative sentence stems caused deeper semantic processing of the incongruous positive adjectives to be bypassed, and (c) negative affective context was generated from reading the sentences even in task conditions where it has not been generated with isolated words.