Event-related potentials in studies of the implicit component of cognitive biases

The review analyzes neurophysiological correlates of the implicit component of cognitive bias in the processes of perception and decision-making. The review identifies the leading methodological pipeline for analysis of the implicit component of cognitive bias, and justifies its choice in terms of the objectives of this review. The method of recording event-related potentials (ERPs) was chosen as the main approach to determining neurophysiological indicators of implicit processes. The analysis of literature allowed us to identify ERP components reproduced in the works of different authors using different variants of experimental designs for studying implicit bias, which may indicate the presence of common neurophysiological mechanisms associated with implicit processes in cognitive bias. The possibility of using other approaches to the analysis of EEG data to obtain new information about the mechanisms of implicit components in cognitive bias is also discussed.

Tactile play and playful massage are a normal interaction between adults and children in many cultures. Experimental data show that activation of the C-tactile system during such playful touches contributes to children’s socialization and the establishment of psychoemotional bonds in the parent-child dyad. However, comprehensive studies of the effects of different types of touch on perception of tactile stimulation in children have not been conducted before. Twenty-three children participated in the present study: 10 in the preschool age group and 13 in the elementary school age group. Children in both groups received play massage containing different types of touch with simultaneous recording of electroencephalogram (EEG) and heart rate. EEG processing included determination of spectral power, alpha rhythm peak frequency and fractal dimension. Analysis of the results showed that the relaxing effect of the procedure was more pronounced in children of primary school age, which can be explained both by the greater maturity of the CNS and the greater need for tactile contact, which is not realized in the school environment.

In this work we solve the problem of automatic binary classification of subjects with a diagnosis of schizophrenia and control groups on a data set obtained on a Siemens 3T tomograph. The data set included 36 subjects undergoing treatment at Psychiatric Hospital no. 1 Named after N.A. Alexeev of the Department of Health of Moscow (GBUZ PKB No. 1 DZM) and 36 subjects from the control group. Machine learning methods were used to solve this problem. As a result, an accuracy of 76% was achieved, which corresponds to the results obtained in other scientific studies. The highest accuracy was obtained for the local homogeneity parameter (regional homogeneity – ReHo), already known in the literature. At the same time, the set of features developed by the authors based on the method for identifying functionally homogeneous regions (FHR) gave a classification accuracy of 74%. But at the same time, the set of FHR features provides higher classification accuracy when using a small number of brain regions. For example, already in 8 regions, the FHR set provided an almost maximum classification accuracy of 72.5% (versus 65% for the ReHo set), which suggests that it is the selected 8 regions that give the highest level of separation.

The purpose of this study is to test the hypothesis that personality traits and stressful situations experienced in childhood could be associated with the level of serum cortisol. The sample included 121 healthy adult men of Yakut (Sakha) ethnicity aged 18 to 27 years. To assess personality traits, the TCI temperament and character questionnaire by R. Cloninger was used. Serum cortisol levels were assessed by enzyme-linked immunosorbent assay (ELISA). It was found that such a temperament trait as “reward dependence” is associated with higher level of cortisol in the blood (p = 0.04). Experienced stressful situations are associated with the character trait “self-transcendence” (p = 0.049) but do not significantly affect cortisol levels. In individuals with high levels of stress, significant correlations were found between the “novelty seeking” (r = 0.33) and “self-directedness” (r = 0.36) with serum cortisol levels, which may reflect the prolonged effect of stress on increasing the sensitivity of the adrenal cortex. The results indicate a possible connection between one of the human temperament traits “reward dependence” and higher levels of cortisol in the blood. A high level of experienced stress situations reduces scores on the character trait “self-transcendence.”

Previously, we found that associations between the STin2VNTR polymorphism of the serotonin transporter gene and cognitive characteristics during aging depend on the intellectual environment of professional activity. In this regard, the present study was aimed to investigate the age-related characteristics of the electrical activity of the brain depending on this polymorphism and long-term intellectual training. We examined EEG power indicators in subjects of the younger (YG, 18–35 years, N = 261) and older (OG, 55–80 years, N = 142) age groups. According to the intellectual richness of the professional activity environment, the subjects were divided into scientists (SA) and those engaged in non-scientific activities (NSA). All subjects were genotyped for the STin2VNTR polymorphism of the serotonin transporter gene. It was found that the power of delta-beta1 rhythms in older carriers of the 10/10 and 12/12 genotypes was opposite in SA and NSA groups (in the SA group 10/10 > 12/12, in the NSA 12/12 > 10/10) while similar effects in young subjects were absent. In the absence of cognitive training, genetic differences were determined by an age-related decrease in the power of delta-alpha3 rhythms in carriers of the 10/10 genotype with no age-related differences in carriers of the 12/12 genotype, suggesting the resistance of the 12/12 genotype to age-related changes. In contrast, under cognitive training conditions, there were no age differences in the 10/10 genotype, and a decrease in power was observed in the 12/12 genotype, suggesting an effect of cognitive training on both homozygous genotypes. The decrease in power observed for the 10/10 NSA and 12/12 SA genotypes appears to have different physiological significance, since it was accompanied by changes in attentional efficiency only in the NSA group. The work shows for the first time that the background EEG features associated with the STin2VNTR polymorphism of the serotonin transporter gene in elderly people are under the modulating influence of long-term cognitive training, determined by the specificity of professional activity.

Recognizing one’s own face is important for self-identification and is considered an indicator of self-consciousness. Social anxiety is related to special attention to self. The aim was to investigate the oscillatory dynamics associated with self-recognition/non-self-recognition in morphed faces and the correlation with social anxiety in these processes. During EEG recordings with 128 electrodes, 48 volunteers (31 females) recognized themselves in morphed faces. During self-recognition, a greater increase in theta rhythm was revealed in the time interval from 800 to 1500 ms than in the non-self-recognition condition. Based on the data on the relationship of the theta rhythm with attention and memory, it could be assumed that the increase in theta rhythm may be related to memory and attention processes when perceiving details, mismatches, and misrepresentation of one’s own face. Social anxiety was positively related to the magnitude of theta rhythm during self-recognition, it could be related to the increased attention that socially anxious people focus on themselves and distortions of their own face.

The role of the sensorimotor component in the processing of verbal information is currently widely discussed. We hypothesize that the type of motor response may influence behavioral and electrophysiological performance in an orthographic decision task. Event-related potentials (ERPs) were recorded in 42 right-handers during an orthographic decision task. Half of the participants were instructed to press the right button with their right hand upon encountering correctly spelled words and the left button with their left hand upon encountering misspelled words, while the other half followed the opposite instruction. The motor response to correctly spelled words was shorter for the dominant hand compared to the non-dominant hand, which may be due to the coincidence of semantic and motor representations (stimulus-response compatibility effect). In addition, reaction times to incorrectly spelled words were longer than to correctly spelled words only in the group of participants who responded with their dominant hand to correctly spelled words. The P200 and N400 ERP components did not depend on the type of motor response. However, in the group of participants who pressed correctly spelled words with their right hand, the amplitude of the P600 component was greater for misspelled words compared to correctly spelled words. Thus, the type of motor response influenced the effects associated with word spelling recognition.

The study of the role of social isolation in the pathogenesis of addictive behavior disorders is an important medical and biological problem. Of particular importance are the limitations of social experience in ontogenesis. This work makes an attempt to find a connection between social isolation in ontogenesis and impulsive-compulsive behavior, as an indicator of the premorbid background for gaming and other forms of behavioral addictions. The mechanisms of addictive behavior in rats reared in isolation (IS) were investigated by analyzing the extracellular release of dopamine in response to stimulation of the positive reinforcing zone. Before the experiments, male rats were kept in individual cages from the 21st day of birth to the 90th day. To study elements of addictive behavior, a variant of the Iowa Gambling Task in a 3-arm maze and a method of developing compulsive overeating using intermittent consumption of high-calorie foods were used. To study compulsive behavior, a marble test was used against the background of withdrawal from a high-calorie diet. Surgeries were performed to implant electrodes into the ventral tegmental area (VTA) and the nucleus accumbens in rats exhibiting elements of addictive behavior in the 3-arm maze. These animals were then trained to respond to VTA self-stimulation. Dopamine release was recorded telemetrically in freely moving rats in response to electrical stimulation of the VTA self-stimulation zone. Fast scan cyclic voltammetry was used to determine changes in dopamine levels in the extracellular environment of the nucleus accumbens. IS entered less into the arm with a high degree of probability but with a low reward, and entered more in the arm with a low degree of probability, but with a high reward, which is associated with the appearance of impulsivity in behavior. In the model of compulsive overeating, the number of approaches to the feeder in IS increased, and against the background of withdrawal of high-calorie food, IS were more active in the marble test. In IS exhibiting elements of addictive behavior in the 3-arm maze, the content of extracellular dopamine in response to electrical stimulation of the VTA self-stimulation zones did not reveal any differences compared to the control group of rats with addictive behavior in the maze. At the same time, IS exhibiting elements of addictive behavior in the maze showed a more pronounced dopamine response to a complex stimulus: a conditioned signal used during maze learning light + VTA stimulation. Thus, rearing in the IS causes an increase in dopamine release in the nucleus accumbens in response to stimulation of the positive reinforcement area associated with addictive behaviors: impulsivity and compulsivity. A conclusion is drawn about the prospects of studying the extracellular release of dopamine and assesses addictive behavior disorders caused by limited social contacts in ontogenesis.

Mice of two strains, selected, respectively, for successful solution of puzzle-box test (addressed to “object permanence” rule operation) and for non-solution of this test, were tested for short term memory, attention to moving object and neophagia. The data obtained demonstrated, that mice, selected for successful “object permanence” test solution demonstrated higher scores in recent memory and attention indices. It was suggested, that interstrain differences discovered should be addressed to differences in the “executive functions” expression.

The intrinsic-signal optical imaging is widely used in experimental, theoretical and applied research of the mammal’s brain neocortex functional anatomy. However, a neural activity signal is hidden by the background activity, the amplitude of which is an order of magnitude larger than the mapping signal amplitude. Most of such background activity represents spontaneous oscillations in 0.01–0.15 Hz frequency range related to vasomotor oscillations. In this paper, we point out that such oscillations change their power and phase during the response time course. The most dramatic influence is intrinsic for 0.05–0.15 Hz oscillations. The power of vasomotor oscillations declines more quickly than the stability features of their phase characteristics. Departing from these data, we suggested approaches for minimization of role of vasomotor oscillations in functional maps resulting from intrinsic-signal optical imaging.