Cortical activation in alexithymia as a response to emotional stimuli.

BACKGROUND Alexithymia has been shown to be related to many psychiatric and somatic illnesses. Aberrant emotion processing in the brain may underlie several psychiatric disorders. However, little is known about the neurobiological underpinnings of alexithymia. AIMS To determine the way in which the brain processes emotion in alexithymia. METHOD The participants were 10 healthy women with alexithymia and 11 healthy women without this condition, recruited into the study on the basis of their scores on the 20-item Toronto Alexithymia Scale. Four films were projected on a video screen to induce each of three emotional conditions (neutral, amusement, sadness). The brain areas activated during emotional stimuli in the alexithymia group were compared with those activated in the non-alexithymia group. Scans of the distribution of [(15)O]H(2)O were acquired using a positron emission tomography (PET) scanner operated in three-dimensional mode. RESULTS In response to emotional stimuli participants with alexithymia activated more parts of their sensory and motor cortices and insula, especially on the left side, and less of their anterior cingulate, compared with the control group. CONCLUSIONS Women with alexithymia seem to over-activate their 'bodily' brain regions, implying a different mode of emotion processing. This may be related to their tendency to experience physical symptoms.