COMT Val(108/158)Met polymorphism effects on emotional brain function and negativity bias.

Area of Science:

• Neuroscience
• Genetics
• Psychiatry

Background:

• Emotional processing biases, particularly towards negative information, are linked to mood regulation and emotional disorders.
• Monoamines modulate these biases, and the catechol-O-methyltransferase (COMT) enzyme plays a key role in dopamine and norepinephrine metabolism.

Purpose of the Study:

• To investigate the impact of the COMT Val(108/158)Met polymorphism on neural responses to emotional stimuli and self-reported negativity bias.
• To explore how this genetic variation affects brain function during conscious and unconscious emotional perception.

Main Methods:

• Collected COMT genotypes and self-reported negativity bias from 46 healthy participants.
• Utilized functional MRI (fMRI) to measure brain activation during the perception of fearful and happy facial expressions under masked and unmasked conditions.
• Acquired structural MRI data to assess gray matter variations.

Main Results:

• The COMT Met allele was associated with increased activation in brain regions like the amygdala and medial prefrontal cortex for conscious fear, and decreased activation for conscious happiness.
• A similar pattern was observed in brainstem activation for masked stimuli, with effects more pronounced in females.
• These neural differences were not attributable to variations in gray matter volume.
• The Met allele-related activation pattern predicted a greater negativity bias, correlating with a higher risk for emotional disorders.

Conclusions:

• The COMT Met allele significantly modulates the neural processing of negative versus positive emotions.
• This genetic influence on emotional brain function may contribute to the development of negativity biases and susceptibility to emotional disorders.