Fear Processing in Dental Phobia during Crossmodal Symptom Provocation: An fMRI Study

Abstract

While previous studies successfully identified the core neural substrates of the animal subtype of specific phobia, only few and inconsistent research is available for dental phobia. These findings might partly relate to the fact that, typically, visual stimuli were employed. The current study aimed to investigate the influence of stimulus modality on neural fear processing in dental phobia. Thirteen dental phobics (DP) and thirteen healthy controls (HC) attended a block-design functional magnetic resonance imaging (fMRI) symptom provocation paradigm encompassing both visual and auditory stimuli. Drill sounds and matched neutral sinus tones served as auditory stimuli and dentist scenes and matched neutral videos as visual stimuli. Group comparisons showed increased activation in the insula, anterior cingulate cortex, orbitofrontal cortex, and thalamus in DP compared to HC during auditory but not visual stimulation. On the contrary, no differential autonomic reactions were observed in DP. Present results are largely comparable to brain areas identified in animal phobia, but also point towards a potential downregulation of autonomic outflow by neural fear circuits in this disorder. Findings enlarge our knowledge about neural correlates of dental phobia and may help to understand the neural underpinnings of the clinical and physiological characteristics of the disorder.

ROI and phobias: The effect of ROI approach on an ALE meta‐analysis of specific phobias

“…The 31 studies included 564 patients with SP and 485 HC (Brinkmann, Poller, Herrmann, Miltner, & Straube, ; Britton et al, ; Caseras, Giampietro, et al, ; Caseras, Mataix‐Cols, et al, ; Dilger et al, ; Goossens, Schruers, Peeters, Griez, & Sunaert, a; Goossens et al, 2007b Halsband & Wolf, ; Hermann et al, ; Hilbert, Evens, Maslowski, Wittchen, & Lueken, ; Killgore et al, ; Lipka et al, ; Lipka, Miltner, & Straube, ; Lueken et al, , ; Michalowski et al, ; Munsterkotter et al, ; Scharmuller et al, ; Schienle et al, ; Schienle, Schafer, Walter, Stark, & Vaitl, ; Schienle, Scharmuller, Leutgeb, Schafer, & Stark, ; Schweckendiek et al, ; Straube, Glauer, et al, ; Straube, Lipka, Sauer, Mothes‐Lasch, & Miltner, ; Straube et al, ; Straube, Mentzel, & Miltner, , ; Wendt, Lotze, Weike, Hosten, & Hamm, ; Wiemer et al, ; Wright et al, ; Zilverstand, Sorger, Kaemingk, & Goebel, ). In six studies, two different subtypes of phobias were considered, with the most studied (24 out of 31) subtype being spider phobia; dental phobia was evaluated in six studies, whereas small animal and blood/injection subtypes in four and three studies, respectively (Table ).…”

“…The first subsample of subjects took part in: Straube, Glauer, et al (); Straube et al (, ); Straube, Mentzel, et al (). The second one was included in: Lipka et al (, ); Straube et al (), and the third subsample participated both in Hilbert et al () and Lueken et al ().…”

Neural circuits in anxiety and stress disorders: a focused review

“…The thalamus is implicated in sensory integration, and functional imaging studies revealed increased activation in the thalamus in response to phobic-related and threat stimuli in patients with SAD, 24 , 25 blood-injection-injury phobia, 26 dental phobia, 27 spider phobia, 28 snake phobia, 29 and PTSD. 30 Contrary to these findings, one study reported that dental phobics did not demonstrate increased activation in thalamus to phobic images.…”

“…Recent functional imaging studies revealed insula hyperactivation to threat in patients with SP, 27 – 29 , 71 SAD, 36 , 50 , 52 , 65 , 72 , 73 and PTSD 30 , 54 , 74 – 77 compared with controls. The degree of insula hyperactivation was positively correlated with symptom severity in SAD.…”

Biased emotional attention in patients with dental phobia

“…Only one study using auditory stimuli (compared to video sequence or pictures) found higher activation in dental phobia patients compared to healthy controls. This heightened activation occurred in areas associated with phobia‐related fear, but again, no increase in autonomic arousal has been observed (Hilbert, Evens, Maslowski, Wittchen, & Lueken, ).…”