Busy behind the scenes – somatoform pain leads to higher temporal activity within a fronto-insular network

Chronic pain at one or more sites without sufficiently explanatory organic pathology can be conceptualized as somatoform pain disorder. An important pathophysiological model of this psychosomatic disease is a disturbed emotional regulation which is reflected by functional and structural alterations in the medial prefrontal cortex (mPFC) and the insula. The strong spatial and temporal coherence of the spontaneous neural activity within these regions during a resting state recently led to the assumption of a fronto-insular network (FIN) dedicated to interoception and personal salience. To investigate putative changes in the temporal activity of this circuit in terms of spontaneous BOLD-fluctuations during a resting state, 21 patients suffering from pain-predominant multisomatoform disorder and 19 age- and gender-matched controls underwent functional 3T-fMRI scanning. Data were analyzed using independent component analysis (ICA). Compared with the control-group, BOLD-oscillations within the FIN showed significantly stronger power densities between 0.2 and 0.24 Hz in the patients which might reflect a higher inner arousal and stressed vegetative state. Our findings provide further evidence for a disturbed functional anatomy in the neural underpinnings of emotional regulation and interoception.

Literatur: Craig, A.D. (2003). Interoception: the sense of the physiological condition of the body. Curr Opin Neurobiol 13, 500-505. Garcia-Campayo, J., Fayed, N., Serrano-Blanco, A., and Roca, M. (2009). Brain dysfunction behind functional symptoms: neuroimaging and somatoform, conversive, and dissociative disorders. Curr Opin Psychiatry 22, 224-231. Malinen, S., Vartiainen, N., Hlushchuk, Y., Koskinen, M., Ramkumar, P., Forss, N., Kalso, E., and Hari, R. (2010). Aberrant temporal and spatial brain activity during rest in patients with chronic pain. Proc Natl Acad Sci U S A 107, 6493-6497.