Ethical issues and challenges in psychological practice and research

Background. The genes responsible for regulating neuro-chemical metabolism are capable of influencing emotional responses. 

Objective. The goal is to determine the influence of the polymorphism of BDNF, HTR2A, and COMT genes on potentials evoked in response to faces with various emotional expressions and objects with different emotional valences. 

Design. The stimuli set included 175 faces and 150 objects with neutral, positive, and negative emotional content. All images were unified in size and brightness and presented for 500 ms. The participants’ task was to determine the emotional content of each stimulus. Each participant’s EEG was recorded at 128 points and averaged in alignment with her responses. Six measures of ERP were recorded for each lead: three for faces with different emotional expressions, and three for objects with different emotional valences.

Results. We discovered that the BDNF and HTR2A gene polymorphism does not affect the visual perception of emotionally charged stimuli as reflected in changes of ERP. By contrast, participants in the COMT Met-Met group differed from participants in groups COMT Val-Met and COMT Val-Val in that their ERPs for both faces and objects were characterized by an increase in P300 amplitude in their frontal, temporal, and parietal areas, predominantly in the right hemisphere. The COMT Met-Met participants were less successful in differentiating stimuli by their emotional valence. 

Conclusion. The COMT gene mutation of the Met/Met type may lead to deficiencies in decision-making about the emotional valence of visual stimuli, as reflected in a substantial increase in the P300 response amplitude.