Association to dopamine receptor D2 (DRD2) with developing fatigue as a result of long-term cognitive load

• Main Authors: Irina S. Polikanova, Alexey V. Korshunov, Sergey V. Leonov, Aleksander N. Veraksa
• Format: Article
• Language: Russian
• Published: Lomonosov Moscow State University 2016-09-01
• Series: Nacionalʹnyj Psihologičeskij Žurnal
• Subjects: fatigue; cognitive load; EEG; individual alpha rhythm; fatigue index; spectral characteristics; dopamine
• Online Access: http://npsyj.ru/pdf/npj-no23-2016/npj_no23_2016_115-126.pdf

This research studies the effect of long-term cognitive load on developimg fatigue on a range of subjective, behavioural (reaction time) and electrophysiological (individual alpha rhythm), fatigue index parameters in carriers of various polymorphisms of DRD2 genes. Mental fatigue was modeled as a result of continuous cognitive tasks aimed at using attention and working memory for 2.5 hours. The sample included 51 subjects (male right-handers, the average age - 20 ± 4 years) whose genetic analysis was conducted and polymorphism options of DRD2 gene Taq1A (A1A1, A1A2 and A2A2) were identified. The research results show that such load significantly affects almost the entire complex of indicators. Significant differences were found between the polymorphisms carriers A1A1 and A1A2 and A2A2 of DRD2 gene polymorphism in the reaction of choice, and also in fatigue index, which reflects the ratio of slow brain rhythms to fast. The results show the positive role of dopamine in developing fatigue. Group of A2A2 («A1») polymorphism carriers was assumed to show lower fatigue, characterized in SVMR and PB significantly slower reaction time, and before and after long-term cognitive load, compared with carriers of polymorphisms A1A1 and A1A2 (« A1 + «). Notably, the dynamics of error increase within all polymorphisms is the same, and genotype number of errors does not vary before or after fatigue. The dynamics of reaction time after the exhaustion of all SNPs is approximately the same. This means that polymorphisms are different not only in dynamics of fatigue but physical predisposition to sensory information processing.