Specific disgust processing in the left insula: New evidence from direct electrical stimulation.

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neurology

Background:

• The specific role of the insula in recognizing facial expressions, particularly disgust, remains debated despite numerous neuropsychological and neuroimaging studies.
• Previous research has yielded controversial findings regarding the insula's precise function in emotion processing.

Purpose of the Study:

• To investigate the selective role of the insula in processing the facial expression of disgust.
• To determine if direct electrical stimulation of the insula impacts emotion recognition.

Main Methods:

• Intraoperative stimulation of the insula in thirteen patients undergoing awake surgery for gliomas near this brain region.
• Assessment of emotion recognition accuracy during direct electrical stimulation of the left insula.

Main Results:

• Direct electrical stimulation of the left insula caused a general decrease in emotion recognition.
• A statistically significant detrimental effect on disgust recognition was observed (p=0.004).
• Happiness and anger were the best and worst recognized emotions, respectively.

Conclusions:

• The findings support a selective role for the left insula in disgust recognition.
• While other negative emotions showed non-significant decreases, disgust recognition was uniquely and significantly impaired.
• The brain's plasticity allows for compensatory networks, as evidenced by preserved disgust recognition post-surgery in some patients.