Neuroscience Letters 388 (2005) 1–6 Brain activation of spider phobics towards disorder-relevant, generally disgust- and fear-inducing pictures Anne Schienle a,b,∗ , Axel Sch¨ afer a , Bertram Walter a , Rudolf Stark a , Dieter Vaitl a a Bender Institute of Neuroimaging, University of Giessen, Otto-Behaghel-Str. 10, 35394 Giessen, Germany b University of Trier, Department of Clinical Psychology II, Universit¨ atsring 15, 54286 Trier, Germany Received 23 November 2004; received in revised form 6 June 2005; accepted 7 June 2005 Abstract The present functional magnetic resonance imaging study investigated the fear and disgust reactivity of patients suffering from spider phobia. Ten phobics and 13 control subjects were scanned while viewing alternating blocks of phobia-relevant, generally fear-inducing, disgust-inducing and affectively neutral pictures. The patient group rated the spider pictures as being more disgust and fear evoking than the control group, and showed greater activation of the visual association cortex, the amygdalae, the right dorsolateral prefrontal cortex and the right hippocampus. Specific phobia-related activation occurred in the supplementary motor area. The patients also showed greater amygdala activation during the presentation of generally disgust- and fear-inducing pictures. This points to an elevated sensitivity to repulsive and threatening stimuli in spider phobics and implicates the amygdala as a crucial neural substrate. © 2005 Elsevier Ireland Ltd. All rights reserved. Keywords: Spider phobia; Disgust; Fear; Visual stimuli; FMRI Spider (SP) phobia belongs to one of the most common anxi- ety disorders with a prevalence of 5.6% in females and 1.2% in males [5]. The disorder is characterized by a marked and persistent fear during the anticipated or actual presence of spiders. Although the sufferers recognize that their fear is excessive or unreasonable, they avoid the phobic situation or else endure it with intense distress [1]. There are numerous indicators that disgust is a crucial disorder-relevant emotion in SP phobia. For example, in questionnaire studies, subjects’ fear of spiders was posi- tively correlated with their disgust sensitivity (e.g. [2,12]). SP phobics also showed stronger disgust responses than non-phobic controls when exposed to spider pictures [20]. Finally, spider-phobic individuals were more likely to refuse eating a cookie that had been touched by a spider due to the disgust they felt [12]. A number of brain imaging studies have been conducted on the neural correlates of SP phobia [3–7,13,15,23]. The majority of investigations involved subjects that were ∗ Corresponding author. Tel.: +49 641 99 26085; fax: +49 641 99 26099. E-mail address: Anne.Schienle@psychol.uni-giessen.de (A. Schienle). exposed to pictures or film clips depicting spiders. Relative to a neutral control condition, the phobogenic stimulation was associated with increased activation in the visual association cortex, especially in the fusiform gyrus [3,6,13], the orbitofrontal and dorsolateral prefrontal cortex (OFC, DLPFC, [3,6,7,13,15]), the hippocampus/parahippocampal gyrus [6,13] and the insula [3,15]. The identified brain regions (particularly the extrastriate cortex, the OFC and the insula) belong to an integrative neural system as described by Rolls [16], which decodes the reward and punishment value of stimuli. This affective regulation circuitry also includes the amygdala as a further central processor of stimulus valence. Interestingly, in only one study [3] amygdala activation was observed during the exposure to phobia-related material. The absence of this effect might be due to the low temporal resolution of positron emission tomography, which was predominantly used [4,6,7,15,23]. Another shortcoming can be seen in the symptom severity of the studied samples. It is not always clear if the patients suffered from clinically relevant disorders. Therefore, in the present study, spider phobics were selected on the basis of questionnaire, interview, as well 0304-3940/$ – see front matter © 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.neulet.2005.06.025