Specific brain processing of facial expressions in people with alexithymia: an H215O‐PET study

Abstract

Alexithymia is a personal trait characterized by a reduced ability to identify and describe one's own feelings and is known to contribute to a variety of physical and behavioural disorders. To elucidate the pathogenesis of stress-related disorders and the normal functions of emotion, it is important to investigate the neurobiology of alexithymia. Although several neurological models of alexithymia have been proposed, there is very little direct evidence for the neural correlates of alexithymia. Using PET, we studied brain activity in subjects with alexithymia when viewing a range of emotional face expressions. Twelve alexithymic and 12 non-alexithymic volunteers (all right-handed males) were selected from 247 applicants on the basis of the 20-item Toronto Alexithymia Scale (TAS-20). Regional cerebral blood flow (rCBF) was measured with H(2)(15)O-PET while the subjects looked at angry, sad and happy faces with varying emotional intensity, as well as neutral faces. Brain response in the subjects with alexithymia significantly differed from that in the subjects without alexithymia. The alexithymics exhibited lower rCBF in the inferior and middle frontal cortex, orbitofrontal cortex, inferior parietal cortex and occipital cortex in the right hemisphere than the non-alexithymics. Additionally, the alexithymics showed higher rCBF in the superior frontal cortex, inferior parietal cortex and cerebellum in the left hemisphere when compared with the non-alexithymics. A covariance analysis revealed that rCBF in the inferior and superior frontal cortex, orbitofrontal cortex and parietal cortex in the right hemisphere correlated negatively with individual TAS-20 scores when viewing angry and sad facial expressions, and that no rCBF correlated positively with TAS-20 scores. Moreover, the anterior cingulate cortex and insula were less activated in the alexithymics' response to angry faces than their response to neutral faces. These results suggest that people with alexithymia process facial expressions differently from people without alexithymia, and that this difference may account for the disorder of affect regulation and consequent peculiar behaviour in people with alexithymia.

Alexithymia, suicidal ideation, and serum lipid levels among drug-naïve outpatients with obsessive-compulsive disorder

“…Alexithymia probably results from an inhibitory mechanism that could contribute to a suppression of emotional processing within the right hemisphere and to poorer verbalization of emotional contents (within the left hemisphere). 38 Kano et al, 39 using positron emission tomography (PET), showed that alexithymic males had lower regional cerebral blood flow in the inferior and middle frontal cortex, OFC, inferior parietal cortex, and occipital cortex in the right hemisphere than nonalexithymics while viewing a range of emotional facial expressions. These findings were also largely confirmed by Berthoz et al 40 in a functional magnetic resonance imaging (fMRI) study.…”

Association between trait emotional awareness and dorsal anterior cingulate activity during emotion is arousal-dependent

“…Individuals who are more emotionally aware are better able to tolerate and consciously process intense emotions than those who are less aware (Kano et al, 2003;Lane et al, 1997b;Thayer and Lane, 2000). Conversely, individuals functioning at a lower level are more likely to behave impulsively and be less aware of what they are feeling in the context of highly arousing emotions (Lane, 2000).…”

Recognition of Emotional Facial Expressions in Alexithymia

“…Several authors hypothesized that hampered regulation of emotion in alexithymia might be based on deficits in the perception and further processing of emotional stimuli (Aleman, 2005;Martínez-Sánchez, Montero, & de la Cerra, 2002;Lane, Sechrest, Reidel, Shapiro, & Kaszniak, 2000). This statement has been empirically supported by imaging data (Kano et al, 2003;Mantani, Okamoto, Shirao, Okada, & Yamawaki, 2005;Moriguchi et al, 2006) and event-related potentials (Pollatos & Gramann, 2011).…”