Disgust regulation via placebo: an fMRI study

Abstract

The present fMRI study investigated whether placebo treatment can change disgust feelings. Disgust-prone women underwent a retest design where they were presented with disgusting, fear-eliciting and neutral pictures once with and once without a placebo (inert pill presented with the suggestion that it can reduce disgust symptoms). The placebo provoked a strong decrease of experienced disgust, which was accompanied by reduced insula activation. Exploratory psychophysiological interaction analyses revealed decreased connectivity in a network consisting of the insula, the amygdala, the anterior cingulate cortex and the orbitofrontal cortex. Moreover, the placebo increased amygdala-DMPFC coactivation. Our findings suggest that placebo use can modulate a specific affective state and might be an option as a first therapy step for clinical samples characterized by excessive and difficult-to-control disgust feelings.

Investigating visual effects of a disgust nocebo with fMRI

“…For example, images related to primary motive states such as visual food cues consistently provoke fusiform gyrus activation relative to non-food items with comparable visual features (see meta-analysis by van der Laan et al [19]). Moreover, in a previous fMRI investigation using the same disgust picture set as in the current study, the contrast Disgust > Neutral was associated with fusiform gyrus activation, which had been significant even in the whole-brain analysis (Schienle et al [15]). These findings suggest that categorization based on the motivational value of stimuli might be another function of the fusiform gyrus.…”

“…We defined those visual brain regions as seeds, which showed significant nocebo-related activation. We chose the amygdala, the insula, and the OFC as ROIs because of their involvement in affective processing and nocebo responsivity (e.g., Schienle et al [14,15]; Wager and Atlas [21]). For the fMRI and PPI analysis, we applied a height threshold of p < 0.005 (uncorrected) and an extent threshold of 10 voxels.…”

“…This change might reflect a greater willingness of the participants to view these stimuli while on the placebo. In a functional magnetic resonance imaging study (fMRI), Schienle et al [14,15] investigated the underlying neuronal processes of the placebo-associated gaze changes. The authors again administered a 'disgust placebo' during the presentation of disgusting images.…”

What’s in a word? How instructions, suggestions, and social information change pain and emotion

“…Parallel to placebo studies on pain, these studies suggest reductions in areas associated with emotional experience such as ACC and AI (Petrovic et al, 2005; Rütgen et al, 2015; Schienle et al, 2014), and often associated increased activations in prefrontal regions including OFC and dlPFC (Benedetti, 2014; Koban et al, in revision; Mayberg et al, 2002; Petrovic et al, 2005). …”

“…While still less studied, progress has been made for placebo effects on other modalities such as depression (Leuchter et al, 2002; Mayberg et al, 2002), negative (Koban et al, in revision; Meyer et al, 2015; Petrovic et al, 2005; Rütgen et al, 2015; Schienle et al, 2014), and positive emotions (Ellingsen et al, 2013) as well. Parallel to placebo studies on pain, these studies suggest reductions in areas associated with emotional experience such as ACC and AI (Petrovic et al, 2005; Rütgen et al, 2015; Schienle et al, 2014), and often associated increased activations in prefrontal regions including OFC and dlPFC (Benedetti, 2014; Koban et al, in revision; Mayberg et al, 2002; Petrovic et al, 2005).…”