[Violation of Assessing the Salience of Information in Schizophrenia].

The history of study of schizophrenia has more than 100 years. During all this period there was collected a lot of data on clinical picture of the disease, psychological peculiarities of patients, biochemical and electrophysiological phenomena. In this respect it becomes actual nowadays to look for a concept that could combine different levels of schizophrenia research (clinical, biochemical, social, etc.) and explain relationships with various symptoms of the disease. In this article we analyze experimental psychological data on thinking of patients, instrumental studies (ERP fMRI, rhythmic patterns of thinking, dopamine theory) and their relationship with clinical implications. It is shown that all these data complement each other and allow us to tell about a basic violation in schizophrenia--the difficulty of patients to differentiate between more and less salient information. We can observe the violation on different levels of schizophrenia investigation and explain different symptoms of the disease as manifestations of that basic violation.

[Cognitive brain­Computer interface and probable aspects of its practical application].

A new type of brain-computer interface was elaborated. It considers a variety of brain activity parameters to determine the type of mental operation being performed at the moment. The corresponding algorithm previously developed in the lab was modified for real-time application. The possibility of interface application for cognitive skills training was investigated. In the proposed paradigm, as soon as the EEG spectral pattern was adequate for the current task, some clue to the solution was presented. As we supposed, such positive biofeedback should facilitate memorization of the current brain state. After just one learning session, the differences in EEG spectra, corresponding two types of tasks, were concentrated in more narrow frequency ranges. It indicates the decrease of mental effort. Moreover, the majority of subjects succeeded to solve the tasks faster, that's an evidence of efficiency increased. The developed interface could be used for the new type of training, based on objective features of brain activity.

[High Variability of Rhythmic EEG Patterns, Intrinsic for Different Type of Thinking in Schizophrenia Patients].

It has been shown in the previously performed experiments that it is possible to "recognize" by the EEG data the type of thinking and to know what kind of task (spatial or verbal-logical) is solving currently. This article describes the application of this technology to the study of schizophrenia patients..We obtained data about the essential difficulty of such recognition in schizophrenia patients, correlation of these difficulties with the severity of negative symptoms. It is shown that the'difficulty of recognition is associated with higher variability of rhythmic EEG patterns, intrinsic for particular type of thinking.

[Comparative Analysis of the Brain Activity during Verbal and Spatial Thinking in Healthy Subjects and Patients with Speech Disorders].

We analyzed the specific brain activity, measured by fMRI in spatial and verbal tasks, in 15 healthy sub- jects and in 9 patients with dysarthria or mild sensorimotor aphasia. In healthy participants, verbal thinking was characterized by activation in Brodmann area 19 and Broca area while specific activation for spatial thinking was observed in bilateral temporal-occipital-parietal areas, left insula, left visual fields 17 and 18. In patients with impaired speech, this distribution of networks specific to a particular type of task underwent significant changes with deactivation of the brain areas, as compared to healthy subjects. Despite the absence of clinical manifestations of cognitive impairment, the average time .to solve verbal tasks was significantly higher, and the percentage of correct answers was less in patients as compared to these values for a group of healthy subjects.

[Determinism and Freedom of Choice in the Brain Functioning].

The problem is considered whether the brain response is completely determined by the stimulus and the personal experience or in some cases the brain is free to choose its behavioral response to achieve the desired goal. The attempt is made to approach to this important philosophical problem basing on modern knowledge about the brain. The paper consists of four parts. In the first part the theoretical views about the free choice problem solving are considered, including views about the freedom of choice as a useful illusion, the hypothesis on appliance of quantum mechanics laws to the brain functioning and the theory of mentalism. In other tree parts consequently the more complicated brain functions such as choice reaction, thinking and creation are analyzed. The general conclusion is that the possibility of quite unpredictable, but sometimes very effective decisions increases when the brain functions are more and more complicated. This fact can be explained with two factors: increasing stochasticity of the brain processes and the role of top-down determinations from mental to neural levels, according to the theory of mentalism.

Effects of genetic variations in the dopaminergic system on fatigue in humans: gender aspects.

Changes in the functional status under the effect of intense mental exercise were studied in carriers of different variants of DAT1, DRD2, and COMT genes. The volunteers (n=140) performed 3-h monotonous mental work (information processing and logical problem solving). The degree of fatigue was evaluated before and after exercise by the HAM (Health status-Activity-Moods) and AMF (Acute Mental Fatigue) questionnaires. A significant relationship between the DAT1, DRD2, and COMT gene polymorphism and changes in the mental sphere status were revealed. The effects of these polymorphisms were the most pronounced in girls. The results are discussed within the framework of hypothesis on the effects of changes in the phasic/tonic dopamine proportion on the studied functions.

Peculiarities of brain information processing in persons with different serotonin transporter gene variants.

Association of brain processes presumably underlying aggression with serotonin transporter gene polymorphism in men was studied. Carriers of more active gene variant are characterized by higher aggression index, increased component of brain potential mismatch negativity responsible for automatic difference detection, and decreased P300 component characterizing involuntary attention and cognitive control.

Effect of functional catechol-O-methyltransferase Val158Met polymorphism on physical aggression.

Genetic and psychological analysis of the relationships between catechol-O-methyltransferase Val158Met polymorphism and various types of aggressiveness was performed in 114 women. Dispersion analysis revealed significant association of ValVal genotype with elevated physical aggression.

Cortical connectivity during word association search.

Cortical connectivity was studied in tasks of generating the use of words in comparison with reading aloud the same words. These tasks were used earlier in PET and high density ERP recordings studies (Posner and Raichle, 1997; Abdullaev and Posner, 1998), in which both the functional anatomy and the time course of cortical areas involved in word processing were described. The wavelet transforms of ERP records and the calculation of correlations between wavelet curves were used to reveal connections between cortical areas. Three stages of intracortical communications while task performance were found. These were: (1) the connections between right and left frontal and central areas which preceded stimulus delivery and persisted up to 180 ms after it; (2) the network connecting right and left frontal with left posterior temporal-parietal junction at 280-450 ms; and (3) communications between left and right temporal zones in 550-800 ms. The data are in good agreement with results of previous PET and ERP studies and supply the earlier findings with circuitry of cortical information transfer.

Correlation of brain rhythms between frontal and left temporal (Wernicke's) cortical areas during verbal thinking.

The aim of this study was to investigate an interaction between frontal and left temporo-parietal cortices in tasks requiring word association. A new method was used to examine averaged event-related potentials in different frequency bands by calculating correlation coefficients between wavelet curves in distant cortical areas. This method was applied to previous event-related potentials recordings which found successive activation of frontal and left posterior areas [1]. Correlated activity at 17 Hz was observed between frontal and left temporal (Wernicke's) areas prior to full activation of Wernicke's area.

Consciousness: criteria and possible mechanisms.

There are two sorts of criteria of consciousness--objective and subjective ones. They are the ability for operating with the knowledge which could be addressed to other people in the abstract form and the feeling of 'ego' as a 'host' of these actions, respectively. These two signs of consciousness are provided with the mechanism based on the synthesis in the brain structures of different kinds of information: sensory information, the data extracted from the memory and the signals from the centers of emotions and motivation. As a result of this synthesis, the sense of 'ego' arises and the message designated for others is determined. A significant role in the informational synthesis is played by dynamic cortical structures--foci of interaction. In perception they are localized predominantly in the projectional cortex, in thinking and in the associative areas. Realization is closely connected with communication and appearance of the interaction foci in the verbal zones of the left hemisphere. Pavlov (1951), in his program lecture in Madrid early in the present century, said that he saw the final aim of his study in the revealing of the mechanism and the inner vital sense of human consciousness. It is important, that Pavlov placed the words 'mechanism' and 'vital sense' near each other, i.e., he considered that the sense of consciousness would be realized through revealing its mechanism. This insight attracts our attention now, when the problem on consciousness mechanism is in scientific plans and the search for the meaning of life by the end of the twentieth century, one full of dramatic events, acquires a special value.

Cortical topography of event-related potentials to winning and losing in a video tennis game.

The event-related potentials (ERP) in frontal and posterior associative cortex in right and left hemispheres were studied in two different outcomes of a television tennis game. These outcomes were 'win' and 'loss' of the ball, the first serving as a model of positive, the second as a model of negative emotional reactions. The ERPs consisted of 4 waves: P300, N600, P800, N1000. The most characteristic interhemispheric difference for 'win' was an increase of N600 in the left posterior associative cortex, and for 'loss', a decrease of P800 in the right frontal area. Thus, the positive and negative emotional reactions have specific spatio-temporal cortical organizations. The topography of ERP related to positive and negative emotions was disturbed in depressive patients. The patients revealed a larger negativity of the right posterior associative cortex and the left frontal cortex waves both at winning and losing the ball.

Event-related potentials associated with positive and negative emotions.

To study the cortical regulation of emotions, event-related potentials (ERP) were recorded in the situation of a television tennis game. Winning the ball was used as a model of a positive and losing it was that of a negative emotional reaction.