Interoception Dysfunction Contributes to the Negative Emotional Bias in Major Depressive Disorder

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Major depressive disorder (MDD) is characterized by impaired interoception and emotional processing.
• Heartbeat-evoked potentials (HEPs) are key indicators of interoception and can be modulated by emotional stimuli in healthy individuals.
• A negative emotional bias is a core feature of MDD, suggesting a potential link with interoception dysfunction.

Purpose of the Study:

• To investigate the relationship between interoception and emotional bias in MDD.
• To determine if interoception dysfunction contributes to the negative emotional bias observed in MDD patients.

Main Methods:

• An electroencephalogram (EEG) study utilizing an emotional faces task.
• Heartbeat-evoked potentials (HEPs) were measured as an index of interoception.
• Late positive potential (LPP) amplitudes were analyzed to assess emotional bias, with HEPs used to predict LPPs.
• Source analysis provided auxiliary sensory-level descriptions.

Main Results:

• Patients with MDD exhibited poorer performance on the heartbeat count task (HCT) and attenuated HEP amplitudes.
• MDD patients showed attenuated LPP amplitudes over centroparietal regions and enhanced LPPs over frontocentral regions compared to healthy controls (HCs).
• Attenuated HEPs in MDD were found to predict aberrant LPPs, particularly under sad face stimuli, suggesting dysfunction in the anterior cingulate cortex (ACC) and right insula.

Conclusions:

• Interoception dysfunction, mediated by the ACC and insula, contributes significantly to the negative emotional bias in MDD.
• These findings underscore the critical role of interoception in the pathophysiology of major depressive disorder.