Left-lateralized fMRI activation in the temporal lobe of high repressive women during the identification of sad prosodies.

We investigated with fMRI whether different lateralization types of cortical activation in prosodic tasks are caused by individually different stress-related coping strategies. After healthy women had been classified as high or low repressive they performed four different identification tasks with acoustically presented speech material while being in the MR scanner. The two materials presented in blocks were emotionally irrelevant CV syllables and adjectives with a mix of different prosodic intonations. Sad and happy intonations had to be targeted by two affective identification tasks in the same adjective mixtures. For testing stimulus-material effects the phoneme /a/ had to be identified both in the syllables and the adjectives. This design allowed us to test influences of coping strategies and affective tasks on cortical activation in both hemispheres. Results showed no differences in global cortical lateralization as a function of high or low repressiveness and no global support for either the valence hypothesis or the right-hemisphere hypothesis of emotional processing. However, we observed differences in auditory and speech cortex. In accordance to the construct of repression/sensitization, high repressive women showed larger left, low repressive women larger right hemisphere activation during the identification of sad intonations. Thus, differences in stress-related coping strategies may not lead to general differences in cortical lateralization, but may depend on specific elicitors and task-relevant brain areas. In contrast, the identification of happy intonations led to strong and right-lateralized global cortical activation independent of coping strategies which complies with the right-hemisphere hypothesis of emotional processing. In addition, this may reflect general cognitive and arousal effects of task difficulty as well as auditory cue-specific attentional effects.