Feelings with no name. In search of a neural basis for alexithymia

PhD ceremony: Ms. K.S. Goerlich, 11.00 uur, Aula Academiegebouw, Broerstraat 5, Groningen

Dissertation: Feelings with no name. In search of a neural basis for alexithymia

Promotor(s): prof. A. Aleman

Faculty: Medical Sciences

Alexithymia (a – ‘lack of’, lexis – ‘word’, thymos – ‘emotion’) is a personality trait characterized by deficits in the processing of emotions, which has been recognized as a major risk factor for a variety of psychiatric and medical conditions. People with alexithymia may or may not experience emotional arousal, and are unable to differentiate between feelings, to distinguish them from physical sensations, and to describe feelings to others. The studies presented in this thesis employed electroencephalography (EEG) and functional as well as structural magnetic resonance imaging (MRI) with the aim to elucidate the neural basis of alexithymia. Our results revealed that people with alexithymia showed reduced electrophysiological responses to variations in the emotional tone of voice and to mismatching emotional speech and music, indicating a reduced sensitivity to emotions conveyed by speech and music in alexithymia. Further, emotion- and mentalizing related brain regions were found to be hyperactive in people with alexithymia as identified by functional MRI, suggesting a need for compensatory brain activation during the prediction of other’s feelings. In addition, our structural MRI study indicated that the tendency of people with alexithymia to rely on bodily signals, when attempting to identify feelings, may have its correlate in enlarged volumes of the right posterior insula. In conclusion, alexithymia seems to be associated with abnormal brain activity during the processing of emotions conveyed by speech and music as well as during emotional mentalizing. In addition to these function deficits during emotional processing, alexithymia further appears to be associated with differences in brain structure.