Self-referential dysfunction and default-mode hyperactivation in psychophysiological insomnia patients: A case-control fMRI study.

In this study we tested whether differences in terms of neural activation are present between a group of PI patients and a healthy-control group while they are exposed to idiosyncratic ruminations and worries, evoked visually by words, so as to explore their hypothetical link with default-mode network (DMN) dysfunction in PI. We recruited five PI patients diagnosed according to the International Classification of Sleep Disorders, version 2 (ICSD-2) of American Academy of Sleep Medicine (AASM) and five age- and sex-matched healthy controls. Patients were recruited at the outpatient Sleep Medicine Centre of the Coimbra University Hospital Centre. We used a functional magnetic resonance imaging (fMRI) block-design paradigm where the participants visualized lists of words related to past/present and future concerns and also emotionally neutral words. The results suggested that the PI patients showed a failure of the DMN to deactivate. Moreover, when these patients were exposed to words concerning both past/present ruminations and future worries, there was a pronounced and significant over-recruitment of brain areas related to DMN and self-referential processing when they were compared to healthy volunteers. The differences between the patient and control groups were also evident in self-report measures. In sum, despite the relatively small sample size, our study clearly suggests that in PI there is a dysfunction in brain regions pertaining to self-referential processing, which is...
Source: Journal of Psychophysiology - Category: Psychiatry & Psychology Source Type: research