Neuroimaging study of affect regulation and culture

To investigate the mechanisms of stress-related disorders, neurobiological study of affect regulation is essential. Recent interesting studies using PET suggest that people with alexithymia process facial expressions differently from people without alexithymia. Although facial expression has been said to be universal, and has been used widely as an emotional stimuli in various neuroimaging studies, the recognition of emotional faces by Japanese individuals is different than that found by other studies in that Japanese often mistake fearful faces for surprised ones. A question remains as to whether or not there are different neural substrates of ‘culture-specific’ recognition of emotional faces. Here we show that different regions of brain activation, as measured by fMRI, were evident in Japanese subjects and non-Japanese subjects of European ancestry who observed facial expressions categorized as “fearful” according to the Ekman criteria. Activation was evident in the posterior cingulate, supplementary motor cortex and the amygdala of the non-Japanese subjects, whereas the right inferior frontal, premotor cortex and left insula were activated in Japanese individuals. The results suggest that the non-Japanese subjects responded to fearful faces in a more direct, emotional way, whereas the Japanese subjects did not attach an emotional value to the faces and therefore activated a template matching system to identify facial expressions. The faces widely used as emotional stimuli were found not to be universally perceived, indicating that cultural specificity should be taken into consideration in such studies. In this paper, we further discuss alexithymia and the results of neuroimaging of the brain from the viewpoint of mind–body interrelationships.