title: Dissociation of neuronal, electrodermal, and evaluative responses in disgust extinction.
abstract: Disgust extinction is an important mechanism relevant for the treatment of psychiatric disorders. However, only a few studies have investigated disgust extinction. Moreover, because disgust sensitivity (DS) is considered as a relevant factor for learning processes, this study also investigated the potential relationship between DS and disgust extinction learning. The aim of this study was to explore the neuronal correlates of disgust extinction, as well as changes in skin conductance responses (SCRs) and evaluative conditioning. Twenty subjects were exposed to a differential extinction paradigm, in which a previous conditioned, and now unreinforced, stimulus (conditioned stimulus, CS+) was compared to a second stimulus (CS-), which was previously not associated with the unconditioned stimulus (UCS). Extinction learning was measured on three different response levels (BOLD responses, SCRs, and evaluative conditioning). Regarding evaluative conditioning, the CS+ was rated as more unpleasant than the CS-. Interestingly, significantly increased amygdala responses and SCRs toward to the CS- were observed. Finally, a (negative) trend was found between DS scores and BOLD responses of the prefrontal cortex. The present findings showed a dissociation of different response levels. The increased CS- responses could be explained by the assumption that the increased amygdala activity may reflect a safety learning signal during the first extinction trials and the subjective focus may therefore shift from the CS+ to the CS-. The correlation finding supports previous studies postulating that DS hampers extinction processes. The present results point toward dissociations between the response levels in context of extinction processes.
authors.affiliation: Department of Psychotherapy and Systems Neuroscience and Bender Institute of Neuroimaging, Justus Liebig University Giessen, Germany. Tim.Klucken@psychol.uni-giessen.de
authors.forename: Tim
authors.initials: T
authors.lastname: Klucken
authors.forename: Jan
authors.initials: J
authors.lastname: Schweckendiek
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Merz
authors.forename: Dieter
authors.initials: D
authors.lastname: Vaitl
authors.forename: Rudolf
authors.initials: R
authors.lastname: Stark
mesh_terms: D000328:Adult; D000679:Amygdala / Q000502:physiology*; D000704:Analysis of Variance; D001931:Brain Mapping; D003214:Conditioning, Classical / Q000502:physiology*; D004644:Emotions / Q000502:physiology*; D005108:Extinction, Psychological / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D005712:Galvanic Skin Response / Q000502:physiology*; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D013997:Time Factors; D014794:Visual Fields / Q000502:physiology; D055815:Young Adult