Erroneously Disgusted: fMRI Study Supports Disgust-Related Neural Reuse in Obsessive-Compulsive Disorder (OCD)

Abstract

Objective : fMRI scans of patients with obsessive-compulsive disorder (OCD) consistently show a hyperactivity of the insular cortex, a region responsible for disgust-processing, when confronted with symptom-triggering stimuli. This asks for an investigation of the role of disgust and the insula in OCD patients. Methods : Seventeen inpatients with OCD and 17 healthy controls (HC) underwent fMRI scanning. Whole-brain contrasts were calculated for “Disgust vs. Neutral” for both groups, plus an analysis of variance (ANOVA) to assess the interaction between group and condition. Additionally, the emotional dimensions of valence and arousal, along with the ability to cope, were assessed by picture ratings. Results : The picture ratings confirmed the patients’ heightened sensitivity to disgust with higher values for arousal and inability to cope, but not for valence. fMRI scans revealed no hyperactivity of the insula in patients compared to controls for the condition “Disgust vs. Neutral,” indicating no basic hypersensitivity to disgusting stimuli. Increased activity in the precuneus in controls for this condition might correspond to the downregulation of arousal. Conclusions : The absent differences in neural activity of the insula in patients compared to controls for the disgust-condition, but heightened activity for symptom-provoking conditions, suggests that the illness is due to an erroneous recruitment of the insula cortex for OCD-stimuli. The finding is interpreted within the framework of the neural reuse hypothesis.

Filthiness of Immorality: Manipulating Disgust and Moral Rigidity Through Noninvasive Brain Stimulation as a Promising Therapeutic Tool for Obsessive Compulsive Disorder

“…Although the current study was conducted-for clear ethical reasons-on a sample of nonpathological individuals, results have potential implications for the treatment of OCD. As described previously, evidence suggests that disgust and deontological morality play a pivotal role in the genesis and maintenance of OCD and points to the role of the insula as one of the putative neural substrates underlying these constructs (e.g., for deontological guilt, see Basile et al, 2014; for disgust, see Viol et al, 2019). In light of this, Buyukturkoglu and colleagues ( 2015 straightforward conclusions from a study with such a limited number of participants is not advisable, this is a remarkable example of how down-regulation of a brain region represents a clinical method for promising treatments.…”

The Role of Insular Cortex in Response to Group Therapy in Vaginismus Patients: Magnetic Resonance Spectroscopy Study

“…This result is consistent with both the studies stating that disgust is an important feeling in vaginismus patients and the studies suggesting that insula plays a role in the neurobiology of disgust. 9,18 Another important point is the fact that impairment in insula was detected in Cho and mIns metabolites. Cho is required for the synthesis and secretion of acetylcholine, 19,20 which is a critical neurotransmitter that mediates memory storage.…”

“…8 Its neurobiology has been investigated especially in OCD patients dwelling on the role of insular cortex. 9 A functional imaging study reported that insular cortex is activated as a response to disgust in both healthy participants and OCD patients. 10,11 Considering that disgust is a factor that makes treatment difficult, it can be thought that metabolic disorder of the insular cortex may be important role at response to group therapy in vaginismus patients.…”

Infection threat shapes our social instincts

“…Indeed, it is especially with regard to sexual matters that women are more easily disgusted than men (Sparks et al 2018 ). A side effect of the difference in disgust between the sexes appears to be that women suffer more than men from disgust-related mental problems like obsessive-compulsive disorder, eating disorders, and animal phobias (Al-Shawaf et al 2018 ; Amoroso et al 2020 ; see also Viol et al 2019 ).…”