Brain response during visual emotional processing: an fMRI study of alexithymia

Alexithymia is found in up to 10% of the general population and is associated with lower quality of life. Alexithymia is a major risk factor for a range of medical and psychiatric problems. Although a deficit involving the anterior cingulate cortex (ACC) deficit is thought to offer the most promising neurobiological model of alexithymia, current studies have yielded inconsistent findings. In this study, neural activity was investigated in well-controlled alexithymic individuals subjected to emotional stimuli. Fifteen individuals with high Toronto Alexithymia Scale (TAS-20) scores (high-alexithymic group) and 15 individuals with low TAS-20 scores (low-alexithymic group) were screened from 432 female college students. Depressive and anxious behaviors were scored using self-rating depression scale (SDS) and self-rating anxiety scale (SAS) questionnaires, respectively. Emotional stimuli consisted of pictures with positive, negative, or neutral pleasantness and high or low arousal of emotional intensity. Regional cerebral activation was measured by functional magnetic resonance imaging (fMRI). The anterior cingulate, mediofrontal cortices, insula and temporal lobe were significantly activated by intense emotional stimuli (negative or positive pictures) in high-alexithymic individuals compared to low-alexithymic individuals. Conversely, high-alexithymic and low-alexithymic individuals showed similar brain activity when subjected to neutral stimuli. Alexithymia is associated with activation in anterior cingulate and mediofrontal cortices during emotional stimuli processing. Therefore, our findings support the hypothesis that altered ACC function may be implicated in alexithymia.