[Saccade latency and pattern of saccade response in the experimental scheme "double step"].

To investigate the decision-making process at the saccade programming we used modification of the "double step" experimental scheme, in which two short stimuli are presented successively in the opposite semifields (puls overshoot--scheme). The dependence of saccades to visual stimuli number, responses pattern (two saccades, or a single saccade to the second stimulus) and the value of saccade latency from the first stimulus duration (150 or 50 ms), the spatial stimuli arrangement and the individual characteristics of the subjects was shown. The findings suggest the relationship of attention and decision making processes at saccade programming and indicate to the possible influence of prognostic processes on the saccadic response "pattern" at the expectation period in the experimental "double step" scheme.

[Cortical potentials evoked to response to a signal to make a memory-guided saccade].

The difference in parameters of visually guided and memory-guided saccades was shown. Increase in the memory-guided saccade latency as compared to that of the visually guided saccades may indicate the deceleration of saccadic programming on the basis of information extraction from the memory. The comparison of parameters and topography of evoked components N1 and P1 of the evoked potential on the signal to make a memory- or visually guided saccade suggests that the early stage of the saccade programming associated with the space information processing is performed predominantly with top-down attention mechanism before the memory-guided saccade and bottom-up mechanism before the visually guided saccade.

[Initiation potential of the brain cortex before memory-guided saccades].

Longer latency and duration of memory-guided saccades and their lower amplitude compared with visually-guided saccades testify to the slower programming of the former. Lateral distinctions in the latencies and durations of memory-guided and visually-guided saccades can reflect leading role of the right hemisphere in programming memory-guided saccades and leading role of the left hemisphere in programming visually-guided saccades. Topography and spatiotemporal dynamics of presaccadic potentials P-1 and N-1 within the last 100 ms of latent period suggest that the mechanisms of final stage of the programming of memory-guided and visually-guided saccades are different.

[Saccadic latency in human with different profiles of functional asymmetry depending on visual space complicity].

The latencies of visually-guided saccades of 47 right-handed subjects (32 with right leading and 15 with left leading eyes) were studied. Stimulation paradigm was spatially bidimentional, and stimuli were presented along horizontal, vertical and oblique axes. Three levels of visual space complicity and two traditional single-step GAP and OVERLAP temporal paradigms were used.

[Attention and eyes movement. Structure of oculomotor system, phenomenology and saccade programming].

In the review modern conceptions of the brain organization of visiomotor system are given. They based on neurophysiological and clinical researches which show reflection of attention processes at various levels of this system. Phenomenological data of saccadic eyes movements and existing models of saccade programming, which expressed on the basis of studying of saccades latent periods variation in different conditions of visual stimulation, are presented.

[Attention and eye movements in human: psychophysiological concepts, neurophysiological models and EEG correlates].

A review. Recently published articles concerning the problem of attention are discussed, the most popular psychophysiological concepts and neurophysiological models of attention are described, and correlation of spatial attention and saccadic eyes movements is shown. The evidence for reflection of attention mechanisms and saccade preparation in intensity and topography of the visual evoked potentials and event-related potentials is given.

[Human fast negative EEG potentials before express saccades].

Fast negative EEG potentials preceding fast regular saccades and express saccades were studied by the method of backward averaging under conditions of monocular stimulation of the right and left eye. "Step" and "gap" experimental paradigms were used for visual stimulation. Analysis of parameters of potentials and their spatiotemporal dynamics suggests that, under conditions of the increased attention and optimal readiness of the neural structures, express saccades appear when the previously chosen program of the future eye movement coincides with the actual target coordinates.

[Effect of dopamine deficiency on the preparation of visually guided saccadic eye movements].

Parameters of saccadic eye movements were studied in patients with Parkinson's disease and control subjects. In parkinsonian patients, the number of slow regular saccades was shown to be increased, and the number of express saccades was shown to be decreased. As a result the mean of saccade latency in patients was longer than in the control group.

Asymmetry of the amplitude-time properties of directed saccades in monkeys depending on the complexity of the spatial scheme of visual stimulation.

Three Macaca rhesus monkeys were used for studies of the performance of visually evoked saccades in single-step changes in the position of a stimulus using standard schemes for presentation of GAP-OVERLAP stimuli. Two spatial schemes were used: presentation of stimuli along the horizontal meridian (one-dimensional) and presentation of stimuli within a rectangular area of the visual field (two-dimensional). Asymmetrical foci of short-and long-latency saccades were found in the visual field.

[Directed attention influence on the human brain potentials under conditions of probability visual stimulation].

Saccadic latency and averaged EEG-potentials connected with switching on of the set and cue visual stimuli were examined in 12 right-handed healthy subjects in M. Posner's "cost-benefit" experimental paradigm. It was shown that attention was reflected in parameters of positive potential P100 evoked by switching on of set and cue stimuli and P300 and slow positive wave PMP1 evoked by switching on of the set stimulus in the relevant conditions.

[Asymmetry of the amplitude-temporal properties of visually-guided saccades in monkeys depending on the complexity of the spatial scheme of the visual stimulation].

The properties of visually-guided saccades were studied in three monkeys (Macaca rhesus). Traditional single-step GAP-OVERLAP temporal paradigms were used. Target stimuli were presented in accordance with two spatial stimulation schemes: (i) along the horizontal meridian (one-dimensional scheme) and (ii) within rectangle part of the visual field (two-dimensional scheme).

[Positive potentials ot the human brain in the latent presaccadic period under conditions of stimulation of the leading and nonleading eye].

We used backward averaging method to study fast positive presaccadic EEG-potentials under conditions of the monocular stimulation of the leading and nonleading eye. Two schemes of the visual stimulus presentation ("no gap" and "overlap") were used. In the "no gap" condition, potential P1 dominated in the hemispere ipsilateral to a saccade direction.

[Cortical positive potentials in the period of eye fixation prior to saccades and antisaccades].

The EEG of 10 right-handed healthy subjects preceding saccade and antisaccade with mean values of latency in the eye fixations period were selected and averaged. The positive potential P2 appearing on the fixation stimuly switching on and slow positive wave following after it were more prominent before antisaccades than normal saccades. Space-temporal analyses of presaccadic potentials showed that right frontal cortex was activated more before antisaccades.

[Potential of the human cerebral cortex prior to antisaccades].

Latencies and other parameters of presaccadic potentials preceding antisaccades and normal saccades to visual stimuli were studied in 10 right-handed healthy subjects. The EEG was recorded in F3, F4, Fz, C3, C4, Cz, P3, P4, O1 and O2 derivation. EEG records preceding saccades and antisaccades with mean latencies were selected and averaged.

[Positive potentials of the human brain at different stages of preparation of a visually triggered saccade].

The EEG of 10 right-handed subjects preceding saccades with mean values of latent periods were selected and averaged. Two standard paradigms of presentation of visual stimuli (central fixation stimulus-peripheral target succession): with a 200-ms inerstimulus interval (GAP) and successive single step (SS). During the period of central fixation, two kinds of positive potentials were observed: fast potentials of "inermediate" positivity (IP) developing 600-400 ms prior to saccade onset and fast potentials of "leading" positivity (LP), which immediately preceded the offset of the central fixation stimulus.

Use of HLDF-6 peptide for correction of disturbances in the endogenous opioid system in offspring of morphine-tolerant animals.

We studied the effect of bioactive peptide HLDF-6 on functional activity of the endogenous antinociceptive system in the offspring of morphine-tolerant animals. Disturbances in this system included changes in the thermonociceptive threshold and enkephalinase A activity in various brain structures. The peptide acted as a potent regulator of the homeostasis in systems responsible for the synthesis and catabolism of endogenous opioids.

[Lateralization of saccadic latency during monocular presentation of stimuli to a leading and non-leading eye].

Saccadic latencies were studied in ten healthy subjects. Peripheral targets were presented monocularly to a leading and nonleading eyes in the right and left hemifields. SS (single step) and OVERLAP (200 ms) schemes of visual stimulation were used.

[Cortical slow negative potentials during eye fixation and preparing of visually triggered saccades in a man].

In 10 right-handed healthy subjects EEGs preceding saccades with mean latent periods were selectively averaged. Two standard schemes of visual stimulation were used: with immediate presentation of a peripheral target stimuli after the central fixation stimulus (a single step paradigm) and with the interval between the stimuli in 200 ms (GAP paradigm). Two waves of slow premotor negativity (early PMN1 and late PMN2) that appeared 930 +/- 79 and 609 +/- 82 ms, respectively, prior to a saccade onset were observed.

Disturbances of saccadic eye movements in monkeys during development of MPTP-induced syndrome.

Changes in the amplitude and dynamic parameters of purposive saccades were studied in monkeys with MPTP-induced Parkinson-like syndrome. Lengthening of saccade latency, decreased maximum velocity of eye movements, and impaired saccade accuracy were observed at the early stages MPTP-syndrome. Different disturbances of large- and small-scale saccades were found.

[A correlation between the efficiency of probabilistic prediction and characteristics of left and right interhemispheric activation].

The interhemispheric difference in the level of EEG activation was studied as a correlate of the efficiency of human probabilistic activity. The interhemispheric asymmetry of the arousal duration in the projection (occipital) and associative (central) areas was assessed in two tested groups of subjects: with an adequate prediction and difficulties in predictive activity under conditions of different information significance of a stimulus. Under conditions of relevant stimulation, the asymmetry coefficient was higher, and the desynchronization reaction in the central areas of the left hemisphere was considerably shorter in bad predictors than in good ones.

[Effect of piracetam on the conditional reflex memory under probable reinforcement conditions].

The effect of piracetam on the development of a two-link system of feed-procuring conditioned reflexes was studied in rats with probability reinforcement. The experiments showed that piracetam improves both the current learning process and the memory track (previous experience) reproduction. In addition, the drug decreases the role of the probabilic character of reinforcement, thus facilitating the synthesis of two reflexes in a united functional complex.

The use of naloxone in small doses in complex therapy of postabstinent heroin syndrome: enkephalinase mechanisms.

The use of naloxone hydrochloride (0.2-0.4 mg) in complex therapy of adolescent heroin addicts significantly prolonged the half-life of serum leu-enkephalin, slightly elevated the thresholds of thermal nociceptive reactions, and improved some clinical indices (considerably reduced drug addiction, eliminated affective disorders, etc.