Brain asymmetry under intermittent normoboric hypoxia

Brain asymmetry under intermittent normoboric hypoxia

282 Posters session 3 / International Journal of Psychophysiology 69 (2008) 276–316 Psychophysiology of Individual Differences. So a great deal of a...

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282

Posters session 3 / International Journal of Psychophysiology 69 (2008) 276–316

Psychophysiology of Individual Differences. So a great deal of attention is paid to the investigation of the psychophysiological peculiarities of intellectually gifted children by psychologists of the Psychological faculty of Southern Federal University (Russia). The aim of this research is to compare the peculiarities of the cerebral hemispheric interactions and interhemispheric asymmetry in the intellectually gifted high school seniors (13–17 years old) with cognitive orientation to natural sciences and to social sciences. With the help of gaploscopical method which is based on the binocular competition the activity of hemispheres and interhemispheric relations of each intellectually gifted child had been measured from the 8-th to the 11-th grades. The results: 1. The intellectually gifted children showed an increase of cerebral hemispheric interactions in thinking process while being involved in the learning activity from the 8-th to the 11-th grades. 2. There is a direct correlation between the increase of the right hemispheric activity in thinking and the development of cognitive orientation to natural sciences in intellectually gifted high school seniors. 3. Among the intellectually gifted high school seniors oriented to natural sciences we have obtained the following results: 4. Subjects with mixed type of cerebral organization showed the highest level of verbal intellect. 5. Subjects with the right-side type of cerebral organization have the highest level of nonverbal intellect. 6. Those who belong to the left-side type of cerebral organization showed the highest level of verbal creativity. 7. Subjects with the combined type of cerebral organization have the highest level of nonverbal creativity. 8. Among the intellectually gifted high school seniors with cognitive orientation to social sciences those who belong to the combined type of cerebral organization have the highest level of general abilities. 9. Increase of the cerebral hemispheric interactions in the intellectually gifted seniors (independent of the basic cognitive orientation) leads to the development of verbal intellect and nonverbal creativity. 10. The obtained results provided a practical application at the Classical Lyceum of Rostov State University for elaborating programmes and methods of teaching, for providing a success in teaching intellectually gifted high school seniors and organizing a psychophysiological basis for the development of their personality taking into account their different cognitive orientation. doi:10.1016/j.ijpsycho.2008.05.246

The systemic temperament characteristics as the base of psychosomatic disorders V.V. Plotnikov, L.A. Severyanova, D.V. Plotnikov Kursk State Medical University, Pathophysiology Department, Kursk, Russia The aim of our study is to determine the individual temperament peculiarities which are associated with the enhanced somatic and autonomic nervous system reactivity and predisposition to psychosomatic disorders. Methods. Of many years study was performed on more than 5000 volunteers aged 18 to 24 years and patients with psychosomatic diseases. In stress and non-stress conditions in a human the computer-apparatus electroencephalography, rheoencephalography, reovasography, electrocardiography, radioassay of hormone levels in blood plasma were used to estimate neurophysiological and

visceral criteria of the CNS activation. The individual temperament characteristics were simultaneously determined by the well-known psychological tests and specially elaborated one to reveal temperament accentuations. Our original test was recognized by the experts of the Institute of Practical Psychology (Imaton Company, S.-Petersburg, 2006) and recommended to be used in clinics over Russia. To estimate the obtained data modern statistics methods were used including the statistical factor analysis and a Student's t-test (p b 0.05). Results. The accentuated individual temperament types in association with intensive generalized CNS activation and enhanced visceral and endocrine responses were found. In stress conditions the persons with the accentuated peculiarities were characterized by the excess of all activity kinds including the intensive subjective experience of strain, as well as cardiovascular and endocrine systems mobilization without the significant improvement of activity efficacy. Close connection between the certain systemic temperament types and individual tendency to be predisposed to different psychosomatic disorders were determined. Thus, the emotional and mixed accentuated types with the predominant sthenic emotions were revealed in the healthy young volunteers with type A behavior as well as in the persons with hereditary predisposition to essential hypertension and own inclination to hypertensive responses to any stress. These data were confirmed by the results of retrospective study of patients suffering from ischemic heart disease. Different accentuated types of individual characteristics were shown in patients with peptic ulcer disease, essential hypotension, repeated spontaneous pregnancy interruptions etc. Conclusion. The concept was proposed that the accentuated systemic temperament peculiarities associate the accentuated formal–dynamic properties of mental processes and enhanced somatic and visceral reactivity. The accentuated types were defined as unbalanced unsteady system predisposing a person to disregulatory disorders. The diagnostics of accentuated temperament types promotes to realize the primary prophylaxis and individualized correction of psychosomatic disorders as well as the rational professional choice. doi:10.1016/j.ijpsycho.2008.05.247

Brain asymmetry under intermittent normoboric hypoxia Y.G. Platonov IF, SD RAMS, Novosibirsk, Russia Cortico-visceral relationship is a key problem for understanding the regulatory mechanisms underlying organismal response to exposure to extreme states of various environmental factors. We developed a particular neurophysiological state reflecting an activation of antihypoxic mechanisms by the help of intermittent normobaric hypoxia (INH). To reveal the involvement of cerebral regions associated with this state the analysis of changing power spectrum was performed analogous with the topographical analysis of coherence between bioelectrical processes in the brain. The correlations between significant levels of EEG coherence and indices of gas exchange and external respiration were also assessed. An altered pattern of respiration with sharply increased sensitivity of the respiration center first to hypoxia and then to hypercapnia is related to the involvement of the brain right hemisphere. Our data on the EEG spectral power mapping showed the displacement of the beta-activity locus to the right side from its initial position in the left hemisphere. A greater involvement of the right hemisphere in the reconstruction of the functional state of the brain

Posters session 3 / International Journal of Psychophysiology 69 (2008) 276–316

as seen from the changes in the coherence level was also found in the EEG beta range. Multiple interhemispheric connections between the left occipital region and the frontal, parietal, temporal or occipital regions of the right hemisphere indicated the formation of “the major center of information processing” in the former brain region. The obtained pattern of the EEG changes showed that increasing exchange between the left occipital region and the subcortical structures involved in the process may occur. The appearance of the beta EEG activity under INH may reflect the activating processes of the ascending system of the reticular formation lateral zones of which are known to contain the neuron structures of the respiratory center. Stimulation of the chemoreceptor's in the sino-carotid and aortal vascular zones might be an underlying basis for the activation of the stem reticular formation as well as the rising rates of high-frequency beta-bands at the initial stages of adaptation and hypoxia. It is reasonable to assume that the reversal of the predominance as well as the involvement of the fronto-parietal lobes with their interhemispheric integration is the determining electrophysiological pattern under INH. Our results suggests that INH may produce the state characterized by the centralization of regulatory mechanisms responsible for the oxygen provision of the organism, the right hemisphere involvement in the control of gas exchange and the changing structure of the afferent information stream. doi:10.1016/j.ijpsycho.2008.05.248

Lateralization of virtual sound sources: Perception of starting and final points of motion trajectories E.A. Petropavlovskaia, L.B. Shestopalova Pavlov Institute of Physiology Russian Academy of Sciences, Hearing Physiology Group, Saint-Petersburg, Russia The ability to localize a moving sound source is an important feature of human perception. Since the 1960's the number of publications connected with different aspects of sound source motion perception appeared. However, moving sound source localization was mainly studied for rather long stimuli. Meanwhile, the electrophysiological studies of spatial hearing often employ relatively short sound signals. Filling this gap could make it possible to find neurophysiological correlations to some psychophysical results. Lateralization of stationary and moving virtual sound sources was studied under dichotic stimulation. The stimuli were the lowpass noise bursts (100 or 200 ms duration). Stationary position or movement of sound image was simulated manipulating the interaural time delay (ITD). ITD was either constant or changed gradually or abruptly from 0 to ±800 µs, corresponding virtual sound source moved from the head midline to each ear. Twelve subjects were asked to localize stationary sound image position or starting and final points of the sound source movement trajectory. It was revealed that starting and final positions of the moving sound image trajectories depended on ITD. Perceived final positions of the moving sound images simulated by stimuli with final ITD value less then 200 µs were displaced far from the head midline in comparison with stationary stimuli of the same ITDs. For ITDs more then 400 µs, gradually and abruptly moving sound sources final positions were closer to the head midline then corresponding stationary sound image position. When comparing the results of both duration conditions, it was shown that for ITDs above 400 µs the final points of gradually moving sound images were lateralized further from the head midline in the case of longer stimuli. Substantial displacement of the moving sound images beginning position in the direction of motion was established. This tendency

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was stronger for gradually moving stimuli than for the abrupt ones and for 100 ms stimuli duration in comparison with 200 ms. This phenomenon could be considered as the Frohlich effect analogue. The results obtained are discussed concerning the spatial auditory attention mechanisms, snapshot and “motion detectors” theories. doi:10.1016/j.ijpsycho.2008.05.249

Visual acuity and oscillatory potentials of subjects with normal vision and emmetropia D.I. Koshelev Russian Eye and Plastic Surgery Centre, Ufa, Russia Purpose. The purpose of this report is to describe oscillatory potentials (OP) of subjects with normal vision and emmetropia in different conditions of light adaptation. Methods. 24 volunteers with normal vision and emmetropia (mean age 21.25 ± 4.5) were tested using a full field electroretinogram in dark adaptation and on rod saturating adaptation light (25 cd/m2). The intensity of the stimulating light was 3 cd s/m2. The oscillatory potentials were isolated by a digital filter 75–500 Hz. The visual acuity (VA) was measured monocularly using the Snellen and Landolt charts. All the subjects were subdivided into two groups in accordance with their VA (1 — 1.05–1.50; 2 — 1.55–2.00). The Student's t-test and correlating analysis were used for the statistical analysis. Results. In scotopic conditions the implicit time of OP 1–3 showed a significant linear correlation to VA (r = −0.50, −0.65, −0.46, accordingly, p b 0.05). There were no significant correlations between VA and amplitudes of OPs. On the contrary in photopic conditions VA showed a significant correlation to the sum of OP (r = −0.48, p b 0.05). Moreover the changes of OPs in photopic condition were different in those groups. Thus against the light background the OP 2 and OP 3 in the 1st group were invisible but in the 2nd group the OP 2 and OP 3 were detected. Conclusions. These results suggest that the functional organization of the neuronal network of the retina plays a significant role in the determination of the spatial resolution of the visual system. Probably the subjects with the highest visual acuity have a specific organization in the feedback contact in the inner plexiform layer of the retina. Consequently high speed and better synchronization of the neuronal processes in the retina accompany the highest visual acuity. doi:10.1016/j.ijpsycho.2008.05.250

The hypothesis about neurophysiological basis of the inner self D.P. Matyushkin Institute for Biomedical Problems, Russian Academy of Sciences, Moscow, Russia The terms “Inner Self” and “Ego System” (ES) that are discussed in the paper, are synonyms. We assume that the Inner self or otherwise Ego-system (ES) consists of two components: the lower Self and the higher Self. The lower Self is based on a subcortical network of monosynaptically interrelated neurons, representing various vectors of attention and behavior (defense, feeding, perception, thinking, etc.) Since these vectors usually compete with one another, most connections between neurons in the network are mutually inhibiting. This network is an