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Biomedical subjects

S A Pogrebinskiĭ

Publications and source records attributed to S A Pogrebinskiĭ.

13 recordsLinked to original sources
PubMed1991

[Relation between cognitive activity of excitable psychopathic personalities and the pattern of reinforcement].

Excitable psychopathic personalities manifest qualitative and quantitative disorders of cognitive activity directly unrelated to emotional reactions. If the result of the activity is estimated by some other person with the aid of positive and negative reinforcement stimuli, deficit of the training is marked to a much greater degree than in cases where the excitable personality itself draws, on the basis of information available in the feedback stimulus, the conclusion whether its decision was right or erroneous.

Adult↗
PubMed1987

[Disorder of selective attention in patients with late-manifesting schizophrenia with a syndrome of involutional paranoia].

Selective attention was studied by registering cortical evoked potentials to acoustic stimuli in mental patients and mentally healthy subjects of old age. Disorder of selective attention in the patients was manifested in an impaired ability of the higher portions of the central nervous system to differentiate between essential and non-essential external stimuli as well as in a weakened inhibition of irrelevant information.

Aged↗
PubMedDate not supplied

[Evoked cortical activity to sounds of differing signal meaning in young and elderly subjects].

In elderly people, in comparison with the young ones, the latency of wave P300 is increased in response to all applied acoustic signals, the amplitude of P300 is lower only in response to significant stimuli. No age changes of the wave N150 parameters are noticed. P300 (or N150) wave amplitude depends on signal significance of the sound; it is the lowest in response to significant stimuli and the highest to the ignored ones. Possible reasons of this paradoxical phenomenon are discussed. Preferential participation of different stages of cortical information processing is determined by the difficulty of perceptive task solution. Cortical electrical reaction to separate stimuli is significantly determined by the context of the information perceived in the given period, creating psychological state of the personality.

Acoustic Stimulation↗
PubMedDate not supplied

[The discrimination of time microintervals by emotionally excitable personalities].

Function of time microintervals estimation was studied in emotionally excitable subjects (23 persons) as well as learning of this function by means of positive and negative reinforcements--words "good" and "error"--and interhemispheric relations. In excitable subjects, discerning is disturbed of short pauses between the visual stimuli, especially of 10 ms pause, presented in the right visual field. Deficit of learning of the intervals discerning is noted by reaction time parameter. There is no advantage of the left hemisphere in discerning the 10 ms pause from 60 ms, which is observed in healthy people.

Adult↗
PubMedDate not supplied

[The effect of masking in the human subject on the solving of a visual-spatial task].

Images of two fragments of regular geometrical figures (square, triangle etc.) have been presented to 58 healthy persons successively with intervals of 20, 80, 120 and 380 ms. The subject must compare these fragments mentally, decide whether they form the standard figure and press a button by the right or left hand according to the instruction. At presentation of both fragments in one visual field, left or right, the number of correct responses is greater when they form the figure. The greater the interstimulus intervals, the greater the number of correct responses to stimuli forming and not forming the standard figure. At presentation of fragments in different visual fields, the number of correct decisions is the same, independently from forming the standard figure. The reaction time is shorter when exposing fragments forming the figure, independently from the way of their presentation; with prolongation of interstimulus intervals the reaction time decreases in all cases. The number of correct decisions is greater and the reaction time is shorter when the stimuli are presented in different visual fields.

Adult↗
PubMedDate not supplied

[Dynamics of cortical evoked activity during human learning to discriminate microintervals of time using feedback].

The dynamics of the cortical evoked activity in the process of learning of time microintervals (10, 60 and 180 ms) discrimination was studied in healthy adults. Feedback stimulus visually informing of the real correlations of the differentiated pauses facilitates the discrimination. The factor of the visual field does not affect the estimation of brief time intervals. At correct identifications, the P300 wave is recorded with a higher amplitude, than at errors. In the trial following the "nonconfirming" feedback stimulus, the standard and test stimuli evoke in the left hemisphere a greater P300 wave, than in the trial after the "confirming" stimulus. Feedback influence is retained in the long-term memory.

Adult↗
PubMedDate not supplied

[Reaction time and interhemispheric interaction].

The study was made on healthy adult subjects. The reaction time of the hand (RT) was measured under two conditions: 1) the choice of reaction (right or left hand) is determined by the nature of the warning stimulus; 2) decision on the choice is taken, depending on the second, trigger stimulus. Stimuli are presented at random sequences to different visual fields. The reaction time to the visual signal presented to the visual field ipsilateral to the hand is significantly shorter (by 15 to 26 msec) than to the stimulus in the contralateral visual field. In a simple motor reaction, when no discrimination of trigger stimulus and the decision on the choice of reaction is required, a hemispheric asymmetry of reaction time is manifested: the left hemisphere only responds differently to direct visual stimulation and to that mediated through the contralateral hemisphere.

Adult↗
PubMedDate not supplied

[Dynamics of interhemispheric functional relations during formation of a functional connection between a visual signal and an unrecognized word].

The study was made on adult humans in a conflict situation. A combination of a non-verbal visual stimulus with an unrecognized emotional word substantially changes interhemispheric functional relations. The latency of the P300 potential in response to the first stimulus becomes reduced in the left occipital area. The potential amplitude considerably diminishes in all the recorded cortical areas (occipital, associative and central), but the reductions more pronounced in the left hemisphere. The nature of the P300 wave changes in response to the conditional stimulus is determined by psychophysiological properties of the "reinforcing" stimulus, in particular by its being non-recognized. Conditioned changes of the P300 wave in tests, where the "reinforcing" stimulus is not recognized, are very stable, and are not extinguished, despite repetitive presentation of the signal without combining it with the emotional word.

Adolescent↗
PubMedDate not supplied

[Interhemispheric functional relationships in the process of "motor command" preparation during choice responses].

Reaction time was recorded in adult healthy people at pauses of 80, 110, 150, 200, 300, 500 and 800 ms between the warning and the triggering stimuli. The warning signal determined the choice of reaction. The stimuli were presented to different halves of the visual field at random. 200 ms pause between the warning and the triggering stimuli is critical for the reaction time. Beginning with this interval, the reaction time was considerably reduced. When information from the triggering stimulus reached "directly" the hemisphere which was "to produce" the motor response, reaction time was considerably shorter, than at non-coincidence of these two factors. The influence of their combination on reaction time is particularly pronounced at 150-500 ms pauses between the warning and the triggering stimuli. The data obtained suggest that the decision making results in a lateralized activation of the hemisphere, which is "to produce" the motor reaction. As a rule, reaction time is not influenced by spatial location of the warning signal. The results of the work should be taken into account when organizing activity of an operator.

Adult↗