Vitali V. Babenko

Background. It is known that some genes regulate neurochemical metabolism, and their polymorphisms affect cognitive performance, including the ability to categorize emotionally significant information.

Objective. The aim of our study was to analyze the recognition of emotional and neutral visual scenes in carriers of different polymorphic variants of the MAOA, COMT, DRD4, and 5HT2A genes.

Design. The study sample consisted of 87 university students (Caucasians, women 63%, average age 20.4±2.6 years). The genotypes of the COMT, 5HT2A, and DRD4 genes were determined by polymerase chain reaction. Agarose gel electrophoresis was used to determine the number of tandem repeats of the MAOA gene. Three hundred sixty (360) photographic images of scenes of different emotional valence (positive, negative, and neutral – 120 images for each category) were used as stimuli. These images were classified by expert assessments. The images were presented in a random sequence. The exposure time was 700 ms. The research participants were asked to determine the emotional valence of each scene.

Results. We found that only the COMT gene genotype affected the recognition of emotional and neutral visual scenes. Carriers of the COMT Val/Val genotype, which causes dopamine to stay in the synaptic space for a shorter time, are better in recognizing and demonstrate higher sensitivity to the emotional content of scenes. Carriers of the Val/Met genotype demonstrated the worst ability to differentiate the emotional valence of visual scenes.

Conclusion. This study has shown that the length of stay of monoamines in the synaptic space regulated by the COMT gene affects the recognition of emotional visual information.

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.