Yu. I. Alexandrov

Neuronal subserving of behavior before and after chronic ethanol treatment

We have previously shown that an acute ethanol dose (1 g/kg), sufficient to impair the performance of a healthy rabbit, also reversibly depresses the activity of those limbic-cortex neurons that are specifically activated during recently learned behavioral acts. Our new morphological and neurophysiological data suggest a death of such neurons after 9-month chronic ethanol treatment. The effect of acute ethanol administration on neurons and performance speed in alcoholic rabbits was opposite to that found in healthy animals. Our results help to understand why neurocognition of alcoholics changes and why acute low-level alcohol ingestion influences them differently than healthy individuals.

Formation and realization of individual experience.

This article describes the methodological approach of systemic psychophysiology. In the framework of this approach a wide range of experimental data is analyzed: results of neuronal recordings in vitro and in awake normal and pathological animals learning to perform and performing both complex instrumental and simple behavioral acts. Another block of analyzed data is based on experiments with human subjects who learn and perform the tasks of categorization of words and operator tasks, participate in group game activity, and answer the questionnaires of psychodiagnostic methods. As a result of this analysis, the systemic psychophysiology approach is used to describe qualitatively and quantitatively the formation and realization of individual experience.

Event-related potentials during individual, cooperative, and competitive task performance differ in subjects with analytic vs. holistic thinking

It has been presented that Western cultures (USA, Western Europe) are mostly characterized by competitive forms of social interaction, whereas Eastern cultures (Japan, China, Russia) are mostly characterized by cooperative forms. It has also been stated that thinking in Eastern countries is predominantly holistic and in Western countries analytic. Based on this, we hypothesized that subjects with analytic vs. holistic thinking styles show differences in decision making in different types of social interaction conditions. We investigated behavioural and brain-activity differences between subjects with analytic and holistic thinking during a choice reaction time (ChRT) task, wherein the subjects either cooperated, competed (in pairs), or performed the task without interaction with other participants. Healthy Russian subjects (N=78) were divided into two groups based on having analytic or holistic thinking as determined with an established questionnaire. We measured reaction times as well as event-related brain potentials. There were significant differences between the interaction conditions in task performance between subjects with analytic and holistic thinking. Both behavioral performance and physiological measures exhibited higher variance in holistic than in analytic subjects. Differences in amplitude and P300 latency suggest that decision making was easier for the holistic subjects in the cooperation condition, in contrast to analytic subjects for whom decision making based on these measures seemed to be easier in the competition condition. The P300 amplitude was higher in the individual condition as compared with the collective conditions. Overall, our results support the notion that the brains of analytic and holistic subjects work differently in different types of social interaction conditions.

Different populations of neurons in relevant brain structures are selectively engaged in the functioning of long-term spatial memory

Using immunohistochemical methods, we studied the expression of the c-fos transcription factor in cells that synthesize the neuron-specific proteins NeuN and calbindin D-28K in the hippocampus, cerebellar vermis, and motor and retrosplenial cortex after training to find a hidden platform in a water maze. We also found apoptotic neural cells that expressed NeuN. We observed significant differences between trained and control rats in the intra- and interstructural distribution of the NeuN- and calbindin-positive neurons that expressed c-fos. We found a correlation between the number of c-fos-expressing NeuN-positive neurons in the retrosplenial cortex and indicators of long-term spatial memory consolidation. We believe that the data we obtained reflect the selective engagement of neurons from different neural populations in relevant brain structures in the functioning of long-term spatial memory.