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Objective: To determine neurophysiological characteristics of patients with long-term follow up (>20 years) and to find correlations between neurophysiological parameters and clinical features of schizophrenia., Material and Methods: The patients were divided into three groups: with predomination of personality changes (group 1, n =17), with negative disorders (group 2, n =23) and with positive and negative disorders (group 3, n =40). A psychopathological method and electroencephalography with evoked potentials testing were used., Results and Conclusion: In group 3, the statistically significant higher frequencies of theta-rhythm and lower of alpha-rhythm were found. Also, theta frequency correlated with PANSS positive scores. The significant intergroup differences by auditory oddball P300 were lacked. The findings are discussed in view of the hypothesis of theta-rhythm as a marker of hippocampal-prefrontal connectivity.

Objective: To study the dynamics of thresholds of the electrically evoked compound action potential of the auditory nerve (ECAP) during neural responce telemetry (NRT) intraoperatively, at the time of activation of the cochlear implantation system (CI) and after 3 and 6 months., Material and Methods: The study included 50 children aged 1 year to 4 years with bilateral sensorineural deafness, operated on by Nucleus CI512 Profile + CP900 CI systems («Cochlear», Australia). In all patients, the electrode array was fully inserted. The dynamics and thresholds of ECAP were recorded and assessed in dynamics: when performing NRT intraoperatively, when the CI system was activated, and after 3 and 6 months. To assess the thresholds, the 1st, 6th, 11th, 16th and 22nd electrodes of the multichannel electrode array were selected., Results: The average threshold values and the NRT threshold profile determined intraoperatively and during measurements at different times after the activation of the CI system were significantly different ( p <0.001), while the average postoperative results were characterized by relative stability. It was shown that the thresholds determined on the electrodes located in the middle of the electrode lattice are more stable than the thresholds determined on the apical and basal electrodes. In most patients, the NRT threshold values determined at the time of the activation of the CI system and after 3 and 6 months were significantly lower than the thresholds determined intraoperatively. The data obtained allow us to conclude that NRT is a stable and accurate technique that allows you to objectify the process of setting up an individual card for the stimulation of the speech processor at the rehabilitation stage after cochlear implantation.

Objective: Amplitude and latency of evoked potential P300 are considered as major correlates of cognitive functions. At the same time the changes in the theta-band event-related oscillations that appears at the same time window as P300 wave are less studied. The purpose of this study was to provide the complex assessment and comparison of neurophysiological indices of cognitive processes in healthy people and patients with personality disorder, schizotypal disorder and schizophrenia with different levels of cognitive dysfunction., Material and Methods: The total number of participants was 124, including 44 healthy volunteers, 40 schizophrenic patients, 22 patients with personality disorder, 18 patients with schizotypal disorder. Patients were examined in standard two-stimulus oddball paradigm. The P300 amplitude and latency, and evoked theta-band power and coherence were identified for target and non-target stimuli., Results and Conclusion: The decrease in P300 amplitude, prolongation of P300 latency, and reduction in the evoked theta-band power and coherence were revealed in all groups of patients compared to healthy subjects. These changes were spatially generalized and the most pronounced in schizophrenic patients. In patients with personality and schizotypal disorders, the changes had a local character, and didn't differ significantly when the groups were compared. The results show the gradual cognitive decline as follows: healthy patients, patients with schizotypal disorder, patients with personality disorder, and patients with schizophrenia. Such cognitive decline might be in line with the reduction of critical and prognostic abilities.

Aim: To study the efficacy of vinpocetine (cavinton comfort) in the treatment of vestibular disorders in patients with chronic cerebral ischemia., Material and Methods: A prospective study included 82 patients (43 men and 39 women, aged 61-75 years, mean age 63,8±5,4 years, with chronic cerebrovascular disease (1-2 stages) with vestibular disorders. Patients were divided into two groups. Patients of the main group were treated with cavinton comfort (10 mg three times per day during 60 days), while patients of the control group did not receive the drug. Subjective and objective symptoms of chronic cerebral ischemia were assessed on a 5-point scale. The results of objective otoneurological examination and auditory evoked potentials were also taken into account in assessing the effectiveness of therapy., Results: The main clinical symptoms comprised vestibular disorders, cephalgia and asthenic syndrome. The reduction in subjective symptoms was noted in 71% of patients in the main group and 34% in the control group and improvement of objective manifestations in 74% and 37%, respectively. The efficacy of cavinton comfort was confirmed by the results of auditory evoked potentials. There was a decrease in the latency of the main peaks and increase in their amplitude (bilaterally)., Conclusion: Cavinton comfort is an effective treatment of vestibular disorders, associated with central lesions of the vestibular system.

Aim: To study the specificity of physiological mechanisms determining the efficiency of modelled purposeful activity in healthy people and patients with epilepsy., Material and Methods: The sample consisted of 235 people, including 72 healthy people (47 men and 25 women) and 163 patients with epilepsy (84 men and 79 women). Emotional and cognitive disorders were scored. Purposeful activity was modelled using the Gorbov-Shulte test. EEG, visual and auditory evoked potentials, P300 wave were recorded. The 'NS-Psychotest' complex was used to record a simple visual-motor reaction, a choice of difference and finger-tapping test. Heart rate variability and external breath functions were studied. An artificial neural network method was used for the prognosis of purposeful activity., Results and Conclusion: The 'resultative' and 'low resultative' groups were selected on the basis of the Gorbov-Shulte test performance. Patients with symptomatic forms of epilepsy, higher frequency of generalized seizures and cognitive disorders were mostly represented in the low resultative group. Artificial neural network classification into groups with different efficiency of activity reveals the greater role of the parameters of afferent and associative mechanisms in healthy people, parameters of cross correlation function of EEG and motor system function in patients with epilepsy.

The risk factors that contribute to the development of hearing loss in the children with chronic kidney failure (CRF) are complications and/or manifestations of the disease itself as well as the side effects of its treatment. There are many similarities between the anatomical, physiological, and pharmacological features of the nephron and the striavascularis of the cochlea. The objective of the present study was the evaluation of the status of the auditory function in the children presenting with CRF., Material and Methods: A total of 62 children with CRF were examined. 40 patients were on peritoneal dialysis and 9 on hemodialysis whereas 13 children did not receive hemodialysis. Kidney was transplanted in 7 patients. The registration of transient evoked otoacoustic emission (TEOAE) was performed in all the children. For patients without TEOAE complex underwent the audiological examination., Results: The TEOAE was not registered in 17 of the 62 examined children. According to the results of the comprehensive audiological examinations, 13 children suffered from the hearing loss of different forms and severity while 5 children presented with bilateral deafness. As the duration of CRF progressed, the patients became more prone to develop hearing impairment. Hearing loss is possibly genetically determined. Among the etiological factors underlying the development of the hearing loss the high doses of immunosuppressants and aminoglycosides are considered to be the principal ones.

This article describes the main clinical features associated with the development and manifestations of disturbed sound perception in the members of the aeronautical personnel engaged in the Russian civilian aviation. The main expert criteria for the relationship between the diseases of the organs of hearing (as exemplified by chronic sensorineural hearing impairment) and professional occupation have been developed based on the results of the clinical and diagnostic examination with the use of whispered and loud speech acumetry, tonal threshold audiometry, speech audiometry, impedancometry and evoked optoacoustic emission. Civilian aviation sectoral approaches to the evaluation of professional suitability in terms of hearing among the aeronautical personnel are considered in accordance with the criteria adopted by the International Civil Aviation Organization (ICAO), a specialized UN agency that sets the international standards for the civilian aviation and co-ordinates its development with the purpose of enhancing the safety and effectiveness of flights. The criteria are formulated for the solution of the expert problems arising from the relationship between the professional occupation and the diseases of the organs of hearing and for the evaluation of the professional suitability in terms of hearing among the aeronautical personnel engaged in civilian aviation.

Aim: The study aimed at analyzing the spatial patterns of evoked event-related oscillations in patients with paranoid schizophrenia and their relationship with clinical symptoms of disease., Material and Methods: Evoked delta, theta, alpha, beta, and gamma rhythms in response to target auditory stimulus in an oddball paradigm were studied in 21 schizophrenic patients and 22 healthy subjects. The independent spatial patterns were revealed within each of the frequency range using the principal component analysis. Each spatial pattern was characterized by the specificity of intra- and inter-hemispheric relations., Results and Conclusion: The schizophrenic patients were characterized by a decrease in the evoked activity in the theta range with the most pronounced changes in the frontal-central areas of the right hemisphere and parietal-occipital areas bilaterally. Associations of the evoked rhythms with PANSS positive and negative symptoms were identified. The study demonstrated the high functional significance of evoked EEG rhythms changes for neurophysiological characteristics of patients with paranoid schizophrenia.

The study analyzed ERPs in 37 healthy right handed subjects without neurological and psychiatric disorders. Young age group consisted of 18 persons aged 18 to 27; advanced age group included 19 persons aged 32 to 59. ERPs were recorded by 32 scalp electrodes according to 10-20% system. Two toned addball paradigm including standard and target tones was used for ERP-recording. The sound sequence was given to examinees without any preliminary instruction. Complex psychology testing included Stroop color and word test for the attention and interference assessment, and Wisconsin card sorting test. Significantly larger amplitude of N200 was detected in young persons in comparison to ones of advantage age. Wavelet-analysis revealed stronger wavelet-connections in frontal-central area on the time range of P300 in persons of advanced age vs. younger ones. The correlation of data of psychological tests examining executive functions was detected with latency of P300 in young examinees and with amplitude of P300 in advanced age ones. Obtained data suggests that switching from one activity to another is prevalence in young persons and focusing on a current activity in advanced age persons.

The objective of the present study was to determine the thresholds of electrically evoked short-latent auditory potentials by the mathematical method and to elucidate the relationship between these parameters and the subjective maximally comfortable levels in the patients undergoing cochlear implantation. The electrically evoked short-latent auditory potentials were recorded in two groups of patients with different stimulation frequency (17 and 43 Hz). The use of the mathematical method of linear regression of the amplitude (peak V) growth function for determining the thresholds of electrically evoked short-latent auditory potentials has a number of advantages over visual detection of the threshold level. To increase the reliability of the data obtained, low stimulation frequencies need to be used when recording electrically evoked short-latent auditory potentials (17 Hz). The calculated thresholds of electrically evoked short-latent auditory potentials can be used to estimate the subjective maximally comfortable levels for the adjustment of the speech processors when it is impossible to register electrically induced stapedial reflexes and electrically induced total action potentials of the auditory nerve in the patients having cochlear implants.

Neurophysiologic data on participation of the critical band mechanism in sound localization and recognition are presented. Single unit activity was recorded extracellularly-in the central nucleus of inferior colliculus of the house mouse females. First, we studied sensitivity of neurons to acoustic signals simulating spectral localization cues (notch noise with different bandwidths). Comparison of neuron responses depending on notch bandwidths revealed that 1/3 octave notch bandwidths was optimal for the analysis of the localization-significant spectral information. This notch bandwidths corresponded to the critical bandwidths of the auditory midbrain neurons evaluated earlier by the simultaneous masking paradigm. Second, we studied selectivity of neuronal responses to the mouse pups' wriggling call, a set of its models and frequency components. The data obtained showed that models of wriggling call frequency components, located as in natural call, in three non-overlapping critical bands produced stronger neuronal responses than other models. We assume that our finding proves the universal role of the critical bands mechanism in processing different parameters of acoustic stimuli. Key words: inferior colliculus, auditory critical bands, sound source localization, analysis of bioacoustic signals.

The present review of the literature is focused on the morphological and functional aspects of antenatal ontogenesis of the hearing system with special reference to the peculiar features of its formation during the post-natal period in the premature infants. In this context, the results of the objective psychoacoustic investigation s are considered (including those obtained by such methods as threshold audiometry, verbal and non-verbal tests, evaluation of central auditory processing of the sound information). Also presented are the results of the objective methods of hearing investigations (acoustic impedancometry, registration of optoacoustic emission and auditory evoked potentials). The underdevelopment of the hearing system in the premature infants manifests itself as the specific functional features of all its components. Their parameters are presented with reference to dynamics of their formation. In addition, the problem of central auditory processing of the disorders that are very likely to be present in the premature infants are discussed.

The present article reports the results of a clinical study of the new wireless device CR120 designed for the intraoperative registration of electrode resistance and the electrically evoked compound action potential (EAP) of the acoustical nerve by means of neural response telemetry. The study has demonstrated the high effectiveness of the application of the new wireless device in clinical practice. It was shown that the registration of electrically evoked compound action potential with the help of the CR120 Intraoperative Remote Assistant took 22% less time than by the conventional method (p<0.001). Moreover, the trial revealed the strong correlation between the threshold EAP values recorded with the use of the new device and by the classical method.

Objective: The search of the structural and functional brain characteristics is one of the most studied directions in the modern biological psychiatry. However, in spite of the numerous studies the results are still controversial. As the necessity of the shift of the current paradigm in schizophrenia research evolves it has been suggested to discriminate not only abnormal but stable functioning neuronal circuits as well. Consequently, the aim is formulated as the search of the minimal brain damage sufficient for disease development., Material and Methods: Author analyzed the auditory oddball P300 latency (as a marker of information processing speed), N-acetylaspartate level in the dorsolateral prefrontal cortex (as a marker of neuronal integrity in this brain area) and fractional anisotropy of the fasciculus uncindtus which connects the frontal and temporal lobes (as a marker of white matter bundles microstructure) in 30 patients with schizophrenia and 27 healthy people., Results and Conclusion: The findings showed that all the tested characteristics are not "obligatory" for schizophrenia.

With the aim to study neurophysiologic correlates and to search for some possible predictors of therapeutic response correlation analysis has been carried out of links between temporal parameters of components of auditory event-related potentials (AERPs) and dynamics of quantitative clinical assessments of mental state conditions in two groups of patients--with depressive-delusional conditions (group 1) and with manic-delusional conditions (group 2) in the frames of attack-like schizophrenia. Statistically significant correlations have been revealed between values of peak latencies of main AERPs components and severity of psychopathologic symptoms before beginning of treatment course, as well as between initial (before treatment course) AERPs temporal parameters and quantitative clinical assessments at the stage of remission establishment. Larger severity of residual positive, negative and common psychopathologic symptoms of schizophrenia (and also of depression and anxiety in group 1) after course of treatment was associated with smaller initial (before treatment course) values of peak latencies of "early" (P1 and N1) and with larger initial values of "late" (P2, N2 and P3) AERPs components in both groups of patients. The data obtained allow to justify basic views on brain mechanisms of affective-delusional disorders, and to reveal possible neurophysiologic predictors of treatment efficacy in such disorders.

The objective of the present study was to collect objective information about the hearing function in the prematurely born infants suffering intrauterine growth retardation (IUGR). The audiological examination of 77 patients at the age of 12 months was performed using two different methods making use of distortion product otoacoustic emission (DPOAE) and evoked auditory steady state responses (ASSRs). Hearing disorders were diagnosed in the children presenting with grade II and III IUGR born prior to the 34th week of pregnancy. The results of the study indicate that the children with grade II and III intrauterine growth retardation born earlier than the 34th week of pregnancy are at risk of developing hearing impairment and should be under dynamic audiological observation with the use of two objective methods, namely DPOAE and ASSR.

The objective of the present work was to study long-term adaptation of the patients to electrical stimulation in the course of rehabilitation following cochlear implantation. The following parameters were determined: variations of threshold auditory sensation of electrical stimulation (ESS), alteration of the maximum electrical stimulation comfort level (MCL), changes in the dynamic range (DR) of the stimulus and changes in the threshold auditory nerve action potentials (ANAP). The observations on ESS dynamics and DR of the stimulus were collected during 2 years after the first connection of the processor in a group of 27 patients. The data obtained from the 3rd, 12th, and 20th stimulation channels were included in the study. The observations on ANAP dynamics were collected during 1 year after surgery in a group of 112 patients. It was shown that ESS variations largely occurred within the first two weeks after connection and did not reach statistical significance. In contrast, MCL and DR changes showed a stably increasing tendency throughout the entire period of observations, with the enhancement of MCL of DR amounting to 25-28% and roughly 50% of the initial values respectively. Threshold auditory sensation of electrical stimulation significantly decreased by the time of the first connection of the implant compared with the surgical data. Further changes in threshold ESS were relatively small and did not reach statistical significance.

Firing activity of 104 neurons located on the medullar dorsal nucleus (a homolog of the complex of mammalian cochlear nuclei) of immobilized common frogs (Rana temporaria) was recorded extracellularly in the absence of external auditory signals. This background activity was analyzed by using the stochastic point process characteristics, such as the variation coefficient, local coefficient of variation, interdependence of the next intervals, the interpulse interval distribution, autocorrelation, and hazard function. All these parameters were compared with the relative number of the interpulse intervals included in bursts ("bursting") that are determined by the offered technique. In neurons with the expressed refractoriness the bursting usually was lower, whereas in neurons with expressed maximum of the correlation function--higher than in the casual Poisson process. However, even in the last group of cells the number of intervals included in bursts was not decreased after casual shuffling of all interpulse intervals. As a result, we have failed to observe any real bursting background activity in the secondary order auditory neurons of the studied amphibian species. The data are compared with features of the background firing in different nuclei of the mammalian auditory pathway.

The present study assessed brain activity changes related to perception of consonant and dissonant chords by musicians and non-musicians. Perception of dissonant chords in non-musicians was accompanied by increase of lower theta activity over right anterior regions, while consonant chords induced greater theta activity over left anterior regions; this pattern of asymmetrical activation was not observed in musicians. ERP analysis revealed that musicians had greater amplitude of early components (P100, N200) than non-musicians irrespective of chord type. The obtained results reflect more efficient musical harmony processing and, possibly, less emotional perception of chords in musicians.

Some structural and functional characteristics of the dorsolateral prefrontal cortex and corpus callosum genu were analyzed in comparison with electrophysiological markers of selective attention in 18 mentally healthy subjects and 22 remitted patients with juvenile schizophrenia. In both topography zones there were no statistically significant intergroup differences in N-acetylaspartate and choline compounds (by proton MR-spectroscopy), whereas fractional anisotropy (by diffusion tensor imaging) in the corpus callosum genu was lower in patients. Absence of significant correlations between the imaging characteristics and psychopathology scores and their weak correlations with P300 suggest a poor involvement of the analyzed structures in the processes which determine cognitive disorders in patients with juvenile schizophrenia.

An integrated neuropsychological study and analysis of cognitive auditory event-related potentials (ERP) using the three-stimulus oddball paradigm was performed in ten subjects who participated in the liquidation of Chernobyl accident and ten healthy subjects. Impairment of higher mental functions, including aspontaneity, fatigability, a decrease in the auditory-verbal and visual memories, and higher motor function deficiency was shown in liquidators. A decrease of amplitude in all components of ERP (N1, N2 and P3) was found in liquidators for all stimuli in both experimental situations (audition of all stimuli and counting of deviant stimuli) compared to healthy subjects. The latent period (LP) of ERP in liquidators was decreased for N1 and N2 components and increased for P3. The largest between-group differences in the LP were revealed in the frontal areas for N1 and P3 in the left hemisphere and for N2 - in the right one. The correlation analysis between the ERP and a neuropsychological study had shown that changes in the LP of N1 are correlated to the impairment of short-term memory and pose praxis of the right hand while changes in the N2 were correlated to the impairment of long-term memory and pose praxis of the left hand. The changes in LP of P3 were correlated to complex cognitive processing disorders. Thus, the complex study identified the deceleration of perception, processing, and analysis of information combined with the weakened inhibition and "uneconomical" type of reactivity which led to the impairment of higher mental functions in liquidators compared to healthy subjects of the same age. The changes found in liquidators are similar to those observed in elderly people and support the hypotheses on accelerated brain ageing caused by low dose irradiation.

Six patients in the state of remission after the first episode ofjuvenile schizophrenia and seven sex- and age-matched mentally healthy subjects were examined by fMRI and ERP methods. The auditory oddball paradigm was applied. Differences in P300 parameters didn't reach the level of significance, however, a significantly higher hemodynamic response to target stimuli was found in patients bilaterally in the supramarginal gyrus and in the right medial frontal gyrus, which points to pathology of these brain areas in supporting of auditory selective attention.

The aim of the study was to investigate the neurophysiologic bases of impairments of motor and some cognitive functions in apathic depression using neurophysiologic and psychophysiologic methods together with clinical assessment of patient's conditions in the dynamics of treatment. Latencies of main components of auditory cognitive evoked potentials (EP) as well as latencies of simple sensorimotor reaction and of two-alternative choice reaction to auditory stimuli have been analyzed. The significant decrease of mean values of the P3 component of auditory cognitive EP in comparison with baseline (before beginning of treatment) level has been noted in patients at the stage of pronounced clinical improvement while latencies of N1, P2 and N2 components have not changed significantly. The mean values of latencies of both simple sensorimotor reaction and of two-alternative choice reaction have been decreased as well. The peculiarities of correlations between clinical indices of depression severity and values of latencies of components of cognitive EP in left and right hemispheric leads in patients with apathic depression indicate the relationship of depression severity with impairment of functional state of the left hemisphere and with activation of the right hemisphere that is in good concordance with contemporary views on the dominant role of the right brain hemisphere in the pathogenesis of depression.

Event-related potentials (ERP) are informative indicators of higher nervous activity of healthy people and patients in pathological states. Traditionally, methods of ERP processing include peak-time characteristics, topographical mapping and localization of equivalent dipole sources. At the same time, estimation of ERP synchronization is complicated by a short duration of the process. The wavelet analysis makes it possible to overcome the disadvantages of the traditional Furrier analysis and to calculate characteristics of ERP synchronization, in particular, phase synchronization. A new approach to estimation of the auditory ERP in healthy persons is proposed in the article. The method is based on the analysis of phase wavelet-synchronization of ERP individual components under conditions of differentiation of different degrees of attention concentration in healthy persons.

The authors analyzed correlations of amplitude and latency levels of N100, N200 and P300 components of acoustic evoked potentials (AEP) registered during sonic stimulation and counting of target-oriented stimuli in 22 patients in vegetative state and mutism as an outcome of traumatic brain injury. Results were analyzed with association of electrophysiological findings with data of diffusion-tensor MRI. 55 healthy volunteers were included into control group. It is described that patients in vegetative state with formal recovery to the level of clear consciousness develop all three components of AEP in response to target-oriented tone. The instruction "to counts" leads to their better development. Patients with restoration to minimal level of consciousness produce all components during audition of sounds and only N100 and N200 in response to standard tone after instruction "to count". It is discovered that levels of amplitude have bigger correlation according to Spearman's criterion with outcome in comparison to latency. There changes are more prominent in N100 and N200 components rather in P300. In addition, after instruction "to count sounds" the registered changes between stages of vegetative state and mutism are significant for leads of left hemisphere, and during audition of sounds--for sagittal leads. The study showed correspondence of acquired changes with MRI data. Chronic unconscious state is associated with changes in corpus callosum (degeneration fibers) and corticospinal tracts in the brainstem. The data are discussed in light of hypothesis of the role of morphofunctional disconnections (brainstem-thalamus and interhemispheric) in impairment of attention and in genesis of different forms of posttraumatic unconscious state.

The influence of rhythmic stimulation on subjective time flow and cognitive processes was studied. Forty four subjects had to categorize abstract, concrete and pseudo words, or duration of stimuli in series with different parallel auditory stimulation (simulated clock ticks with increased (1.25 Hz), normal (1.00 Hz) and decreased (0.75 Hz) rates), or without stimulation (control block). The reaction time was shown to be smaller under conditions of the decreased clock rate as compared to the increased rate or the absence of stimulation. The subjective duration of the series was also shorter in the first case. EEG data revealed the higher amplitude of the P300 component of the event-related potential and the lower alpha-rhythm power under conditions of stimulation with the decreased clock rate as compared to the increased rate.

In 22 healthy participants EEG from 28 channels was recorded during visual presentation of a random sequence of words and pseudo-words. The experiment consisted of three parts. In the first part the subjects just passively read the stimuli, in the second part they had to click the mouse button when seeing a word and in the third part--when seeing a pseudo-word. The results show that words are more significant to subjects than pseudo-words causing higher amplitude of P100 and P300 in the first and the second parts of the experiment, evidently, due to presence of meaning. However, the lexical task may be a more significant factor of the information processing than the presence of meaning, since in the third part of the experiment, where pseudo-words were relevant, they elicited higher amplitude of P300 than words. Pseudo-words elicited also negative N400 amplitude than words, revealing incongruity effect. However, when words were task-incongruent, this effect is significantly less evident.

The DRD2 Ser311Cys polymorphism was studied in a sample which included 366 patients with schizophrenia and 387 healthy controls. The frequency of the Cys allele was significantly higher (p<0,009) in the group of patients compared to the controls (8,5% and 3,9%, respectively). Sustained attention assessed by P300 parameters was studied in 66 patients with the SerSer and SerCys genotypes (the CysCys genotype was not observed in the sample studied). A significant effect (p=0,01) of the SerCys genotype on P300 latency in frontal, central and temporal regions was found. Patients with the at-risk allele presented delayed latencies that reflected the lower speed of mental processes related to activation of attention resources. In conclusion, our data support the evidence of association between the Cys allele and schizophrenia obtained earlier for other populations and revealed that carriers of the genotype containing the at-risk allele had delayed P300 latencies.

Variations of non-linear dynamic operations in of alpha-band of the EEG are reflected in the peculiarities of the P300 wave cortical field organization. In high-dimensional chaotic processes this field is characterized with high values of integral indices of its activity, the spatial synchronization of generating process as well as with the prevalence of P3a wave generation. The diversity of spatial combinations of P-wave sources reflects the high rate of their spatial complexity organization. The main contribution into this activity is made by symmetrical points of anterior and temporal cortical portions. In low-dimensional dynamics the spatial structure of the positive wave is simplified. It becomes less global and more differentiated. P3b wave generation prevails in this case. The values of integral indices of wave cortical field activity are reduced. The focal topography of positive waves and their sources changes. Chaotic systems of alpha-band wave generators demonstrate good controllability and high plasticity in contingent acoustic stimulation. They change their dynamic characteristics due to biofeedback control, determining thereby P-wave field organization.

To search for EEG-correlates of emotional processing that might be indicators of genetic predisposition to schizophrenia, changes in EEG spectral power during perception of neutral and emotionally salient words were examined in 36 schizophrenic patients, 50 of their unaffected first-degree relatives, and 47 healthy individuals without any family history of psychoses. In healthy persons, passive listening to neutral words induced minimum changes in cortical rhythmical activity, predominantly in the form of synchronization of slow and fast waves, whereas perception of emotional words was followed by a generalized depression of the alpha and beta1 activity and a locally specific decrease in the power of theta and beta2 frequency bands. The patients and their relatives showed a decrease in the alpha and beta1 activity simultaneously with an increase in the power of delta activity in response to both groups of words. Thus, in the patients and their relatives, reactions to neutral and emotional words were ulterior as a result of augmented reactions to the neutral words. These findings suggest that the EEG changes reflect familial and possibly hereditable abnormal involuntary attention. No prominent decrease in reactivity to emotional stimuli was revealed in schizophrenic families.

A phenomenon of a mismatch of the bimodal ERP and the sum of unimodal ERPs was used in our research. It was investigated how the mismatch amplitude depends on audio-visual integration effectiveness. The effectiveness was calculated on basis of approximation degree of an experimental performance to parameters of "ideal observer". It was determined, the higher the subject's integration effectiveness is, the rostraler the mismatch focus localization is. The highest correlation of the mismatch amplitude and the audio-visual integration effectiveness was revealed in the left frontal cortex.

The changes in the parameters of average latent auditory potentials (ALAP) were studied in 23 adult patients under anesthesia (ASA II-III) during elective abdominal operations. General combined anesthesia (propofol, fentanyl, and N2O) were used in Group 1 (n = 12), it was combined with epidural anesthesia (lidocaine) in Group 2 (n = 11). General anesthesia was shown to cause a reduction in the amplitude of Pa and Nb peaks and an increase in their latency. Surgical nociceptive stimulation, on the contrary, increased the amplitude of these peaks and decreased their latency. When general anesthesia was applied alone, the magnitude of changes was ascertained to be significantly greater than when it was combined with epidural anesthesia. This suggests that the changes in ALAP reflect the full value and the degree of nociceptive current suppression.

Auditory event-related potentials (ERP) were registered to the dichotically presented white noise stimuli (duration 1500 ms, band 150-1200 Hz). Abrupt or gradual change ofinteraural time difference in the middle of stimuli (750 ms after sound offset) was perceived as an apparent auditory image (AI) instant relocation or motion from the midline to one of the ears. In responses these stimuli two ERPs were observed: one to the sound onset, and second--to the onset of motion or AI relocation. ERPs to AI relocation differed from those to sound onset in longer components latencies (123 ms versus 105 ms for N 1,227 ms versus 190 ms for P2). In responses to AI motion component latencies were even longer (N1: 137 ms, P2: 240 ms); N1 amplitude was greater at sites contralateral to the AI motion direction.

A hemispheric interaction during verbal creative thinking was studied by the analysis of EEG coherence in the band of 4-30 Hz. 18 males and 21 females (right-handed university students) participaited in the experiments. Independently of gender, the performance of Remote Associates Task was accompanied by an increase in coherence in the theta1 and beta2 frequency bands as compared to the states of rest and the letter-fluency and simple associate's tasks. Successful search for original word associates as compared to generation of standard words was accompanied by a local increase in the interhemispheric coherence of the beta2 rhythm mostly in the parietotemporal cortex. In creative men, the increase in the hemispheric interaction efficient for a search for original words was focused in the frontal and temporal loci of the right hemisphere and in the left occipital locus, whereas in creative women the increase in coherence was observed in the left frontal and temporal regions. Creative men differed from non-creative ones by higher inter- and intrahemispheric coherence and were similar to women in the level of hemispheric interaction. The cortical distribution of foci of interhemispheric coherence reactivity indicates that the cortical organization of verbal functions depends on both sex and creativity of men and women.

In this paper we aimed at studying brain structures involved in intermodal attention and memory processes. This was accomplished by dipole modeling of the difference waves of event-related potentials recorded during the performance of verbal tasks and in the control condition. The models were constructed independently from each other for six difference waves obtained by subtracting different experimental conditions. The majority of equivalent sources were located in temporal and frontal areas. The differences in the evoked activity observed between task conditions in the interval from 450 to 850 ms are mainly related to variations in the activity of the hippocampus and adjacent structures.

Responses of 93 single units of the human thalamic CM-Pf complex to relevant and irrelevant verbal (or sensory) stimuli were studied using microelectrode technique in alert diskinetic patients suffering from the tonic forms of spasmodic torticollis during 11 stereotaxic operations. The response patterns of two types units with irregular unitary (A-type) and low-threshold bursting Ca(2+)-dependent (B-type) spike activity were studied. Three main conclusions emerge from the studies: 1) high reactivity of both A- and B-units to presentation of relevant verbal stimuli with differences of their response patterns as determined by the type of constituent elements; 2) close functional connectivity of these neuronal changes with the level of selective attention; 3) at the moment of attention activation, the appearance of transient interneuronal interactions between adjacent A and B cells characterized by the local synchronization and stabilization of rhythmic oscillations. These data point to considerable contribution of the thalamic CM-Pf complex and its neuronal mechanisms into organization of the human selective attention and triggering verbal-related processing during performance of purposive speech-provoked voluntary acts.

The changes of P300 parameters (lower amplitude and increased latency) are thought to be the most prominent phenomena of schizophrenia. A role of gene polymorphism in P300 generation was supported by several associative studies in psychiatrically well subjects and patients with mental disorders. We studied P300 parameters and the following polymorphisms: T102C for the serotonin receptor type 2A (5-HTR2A) gene, the 5-HTTLPR for the serotonin transporter gene, -809G/A, -616G/C N -52C/T SNPs in the promoter region of the dopamine D4 receptor (DRD4) gene and the Val158Met polymorphism of the catechol-O-methyltransferase (COMT) in 74 patients with schizophrenia and spectrum disorders and 71 their first-degree relatives. No association was found between serotonergic system genes and P300. The -809G/A DRD4 gene polymorphism was related to amplitude in all frontal leads (p=0,01) in patients. In relatives, an association was observed between -521C/T DRD4 variants and latency (p=0,005) as well as between the COMT gene polymorphism and P300 amplitude (p=0,004) at the central lead. Thus, the genes involved in dopaminergic system play a role in P300 generation both in patients with schizophrenia and spectrum disorders and their relatives.

A relationship between neurophysiological and psychological characteristics of attention was studied in 18 patients with schizophrenia and their 34 mentally healthy relatives: parents and siblings (20 subjects) and children (14 subjects). In patients, a decrease of P300 auditory evoked potentials significantly correlated with disturbances of attention stability and volume as well as characteristics of involuntary attention. At the same time, in the groups of relatives the anomalies of attention stability and attention in conditions of prolonged concentration were positively related to P300 latency.

Relation between leukocyte elastase (LE) activity of peripheral blood and temporal parameters of late cognitive component of event-related potentials (ERP) was studied in 36 patients with different types of schizophrenia and 28 healthy controls. Both P300 latency and amplitude correlated with LE activity in patients, but not in controls. The results suggest a relationship between innate immunity activation and pathophysiologic processes underlying cognitive impairment in schizophrenia. Possible mechanisms of the correlations revealed are analyzed.

Parameters of cognitive evoked potentials P300 were studied in 40 patients with ischemic heart disease subjected to coronary artery bypass graft surgery in conditions of cardiopulmonary bypass before and 7-9 days after operation. Patients underwent also neurological and neuropsychological examination. The most significant P300 parameters proved to be P3 and N2 latency, an increase of which correlated with the level of developing cognitive deficiency. A neuroprotective effect of Tracilol during the surgery was confirmed. In patients receiving this drug, cognitive deficiency and changes of P300 parameters were less pronounced. A study of cognitive evoked potentials P300 may be recommended for detecting early cognitive dysfunction and estimation of neuroprotective therapy in patients operated on in conditions of cardiopulmonary bypass.

Somatosensorially evoked and auditorially evoked potentials (SSEP and AEP) were evaluated in 75 patients in different stages of general anesthesia during surgical procedures made on the lungs. N19-P23 latent increases of SSEP denoted an adequate level of analgesia. The AEP evaluation is recommended for monitoring the amnesia status during general anesthesia. N1 depression, long-latent N2 and P300 as well as disappearance of AEP and intracerebral asymmetry inversion with predominance of the bioelectric activity in the right cerebral hemisphere are regarded as objective signs of amnesia induction.

Some problems related with vertigo belong to saccular malfunctions. The purpose of this case study was to analyze the vestibular induced myogenous potentials (VIMP) isolated from responses to an acoustic stimulation of the internal ear. The suggested technique is based on modeling each average response as an autoregression process (AP). The spectral analysis of a singal, representing a temporal evolution of the AP parameters, was shown to be applicable for studying the VIMP time dynamics. The method can be used as an instrument in classifying the vestibular pathologies.

We found that the mismatch negativity (MMM) was absent in evoked potentials in passive condition for frequency deviant acoustical stimuli when stimulus duration was only 11-30 ms. But it was shown that it is possible for participants to fairly well discriminate these stimuli and the component N2b in RP was generated without preceding MMN. Processing negativity also was absent in potentials by the minimal stimulus duration (11 ms). Auditory discrimination nevertheless was still possible, but reaction time and number of committed errors increased significantly.

Brain electrical activity during habituation to repeated verbal stimulus was recorded in subjects with high and low levels of personal anxiety. During habituation of subjects with low anxiety, the spectral power of EEG alpha and theta bands increased in the frontal cortical areas. Such a reaction was not observed in subjects with high anxiety level. Moreover, during habituation traces, the latency of P300 of the auditory evoked potential increased. This parameter did not depend on anxiety level. The amplitude of P300 in the right temporal region was shown to be related to anxiety level: it increased after habituation in subjects with low anxiety and did not change in subjects with high anxiety.

The study was made of relationship between the dynamics of neurophysiological parameters and the changes of clinical state assessed by the PANSS and the CGI in 17 male patients with schizophrenia. Significant correlations between the reduction of psychopathological symptoms by PANSS and an increase of P300 amplitude and spectral density of background EEG in delta-, theta-, alpha 1- and alpha 3-ranges and the reduction of psychotic symptoms by CGI and an increase density in delta-, theta-, alpha 1-diapasons were found. The findings are considered as the evidence of correlations between an improvement of clinical state and "normalization" of different processes of attention, thinking and memory reflected changes of the tested EEG parameters.

Neurophysiological characteristic--an amplitude of P300 auditory evoked potentials (EP) wave registered in 12 and 5 EEG leads--was studied in 22 patients with endogenous psychoses. Using cluster analysis, it was shown that the differences between the EP amplitudes before and after treatment split into clusters thus indicating a fine structure of the data, reflecting an objective changes in the patient's state during the treatment. The results obtained correlated with an evaluation of patient' clinical state by the PANSS, namely with scores on general psychopathological and positive symptoms subscales.

The peculiarities of brain electric activity in mentally normal parents of schizophrenics (52 subjects) as compared to the control group of mentally normal subjects without family history of manifest psychosis (22 subjects). In both groups, EEG spectral densities and auditory evoked potentials (AEP) characteristics were compared. The parents of schizophrenics appeared to differ from controls by decrease of N1 amplitude and prolongation of N2, P3 which was similar to that observed in patients with schizophrenia. The findings are discussed as evidence of heritability of deviations in cognitive processes.

The aim of the study was a comparative analysis of spatial-temporary organization of P300 acoustic evoked potential (AEP) in patients with local lesions of the brain stem, frontal and temporal structures in the situations of "passive" listening to sounds and their active recognition (a count). Specific changes of P300 parameters were distinguished in each group. The peak-temporary P300 parameters--latency increase, decrease of amplitude and tendency to the decrease of half-cycle--were similarly changed, irrespective of brain damage topography. A degree of the changes correlated with a level of functional acoustic evoked potential decompensation. In relation to pathologic process location, the topographical P300 AEP features were more specified, comparing to peak-temporary parameters. An existence of two systems for P300 generation at "active" counting and "passive" listening was suggested. In "passive" listening, a response is mostly determined by intact left frontal lobe and middle-stem structures but in "active" counting--by intact right frontal lobe or lobes and limbic system structures (hippocampus).