Altered olfactory processing and increased insula activity in patients with obsessive-compulsive disorder: An fMRI...

Area of Science:

• Neuroscience
• Psychiatry
• Neuroimaging

Background:

• Obsessive-compulsive disorder (OCD) is associated with heightened insula activation to visual disgust stimuli.
• Previous research has not investigated olfactory processing in OCD using functional magnetic resonance imaging (fMRI).

Purpose of the Study:

• To investigate olfactory neural reactivity in individuals with OCD compared to healthy controls (HC).
• To explore the relationship between olfactory activation, disgust sensitivity, and OCD symptom severity.

Main Methods:

• fMRI was used to measure brain activation in 15 OCD patients and 15 HC participants.
• Participants were exposed to pleasant and unpleasant odors, as well as unscented air.
• Correlations were examined between neural activation and measures of disgust sensitivity, anxiety, and OCD symptoms.

Main Results:

• OCD participants showed increased left anterior insula activation to unpleasant odors compared to HC, correlating with disgust sensitivity.
• OCD participants exhibited increased caudate nucleus and insula activation to pleasant odors, correlating with OCD severity and anxiety.
• Heightened anterior insula activation to both pleasant and unpleasant odors was observed in OCD patients, linked to OCD symptoms and disgust sensitivity.

Conclusions:

• OCD patients display altered neural responses to odors, suggesting a potential negative cognitive bias in emotional processing.
• These findings enhance understanding of the neural mechanisms underlying OCD.
• The results may inform the development of targeted therapeutic interventions for OCD.