Vol 73, No 3 (2023)

In recent decades, the use of instrumental methods has significantly expanded the diagnosis of signs of consciousness in patients with chronic disorders of consciousness (DOC). The phenomenon of “covert cognition” was described with their help. This review highlights studies on the detection of “covert cognition” in patients with DOC using functional magnetic resonance imaging. Most types of passive and active paradigms used for this purpose are analyzed and systematized. Special attention is paid to an integrated approach with a combination of different paradigms and research methods. The importance of detecting the phenomenon of “covert cognition” for the neurorehabilitation of patients with DOC is emphasized.

The study of mirror neurons (MN) has a long way since its discovery on monkeys and later on humans. However, there are inconsistencies on the way that stimuli are presented and on the time of stimuli presentation. Which is the optimal way to present motor movement stimuli? Is it possible to estimate the time course of the mirror neurons effect by using transcranial magnetic stimulation at specific time windows? In the current study we investigated different type of stimuli presentation (photo and video of hand movements) by using single pulse Transcranial Magnetic Stimulation of the dominant primary motor cortex (M1) at different time windows (0, 320, 640 ms). Motor evoked potentials from FDI (index finger muscle) and ADM (little finger muscle) were recorded on 11 healthy subjects at rest with their hands in orthogonal position while only observing the visual stimuli in three different presentation conditions. Our results showed that Video presentation induces the strongest mirror effect at 320 ms from the movement onset. This effect is muscle specific. The current evidence provides an optimal protocol for the investigation of the mirror neurons system in humans and pave the way for future clinical application and rehabilitation.

The study involved 45 students (all men) of different nationalities (mostly Tajiks and Kyrgyzs) aged from 17 to 28 years who had moved to the conditions of the North (Yakutsk, Republic of Sakha (Yakutia)). The aim of the study was to investigate the balance of connectivity of resting state networks in the first condition, when the participants got into a new unfamiliar environment and in the second condition after one year of staying in these conditions. A 128-channel EEGs were recorded at rest. Connectivity measures were calculated between nodes of resting state networks and the rest of the brain. Connectivity contrasts Attention Networks vs Default Mode Network in the first and in the second conditions were performed. In the first condition, a predominance of Attention networks over Default mode network was revealed, which could be related to an increased attention to new stimuli and tasks in a new unfamiliar environment. In the second condition, after one year of staying in these environmental conditions, the balance of resting state networks shifted toward a predominance of the Default mode network over Attention networks.

We studied the reactivity features of the EEG mu rhythm amplitude in the individually determined frequency range, as well as the beta rhythm in the central, frontal and parietal EEG leads in children while performing tasks for instrumental, emotional and altruistic helping behavior. The study engaged 24 children aged 4 to 7 years. ANOVA showed a significant decrease of the mu rhythm amplitude in the central and parietal regions, which is supposed to be associated with the activation of the mirror system of the brain. When performing tasks for instrumental and altruistic helping behavior, there was an increase in the amplitude of the beta rhythm in the frontal, central, and parietal regions, which may be associated with children observing actions that are emotionally charged and cause empathy with a person in need of help. The more the beta rhythm increased, the sooner the children provided help, which can be explained by a greater degree of emotional involvement and activation of cognitive processes in children with high performance of prosocial behavior.

Sex and strain differences in the passive avoidance learning and extinction in male and female of DISC1-L100P mice and wild-type control mice were investigated. It was shown that male and female mice of both strains were well trained in the conditioned response of passive avoidance, but differed in fear memory extinction, the ability to form a new memory trace about the safety of the previously punished dark compartment of apparatus in the procedure of repeated testing. There was a deficit of fear memory extinction in females of DISC1-L100P and C57BL/6 mice compared to males. At the same time, interstrain differences in the dynamics of passive avoidance extinction in female mice of these strains were revealed. Results also showed that DISC1-L100P males differed from C57BL/6 in terms of the time to achieve complete extinction of this reaction.