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Biomedical subjects

Koptelov YuM

Publications and source records attributed to Koptelov YuM.

4 recordsLinked to original sources
PubMedDate not supplied

Electroencephalographic correlates of neurological disturbances at remote periods of the effect of ionizing radiation (sequelae of the Chernobyl' NPP accident).

The psychoneurological status of 40 participants (all men aged 25-45 years, official dose 15-51 rem) in the liquidation of the consequences of the accident at the Chernobyl Nuclear Power Plant in 1986-1987 was investigated; EEG mapping and three-dimensional localization of the sources of epileptic activity as compared with the data of healthy individuals (20 individuals) was carried out. Vegetative-vascular symptomatology was identified in the neurological status of all the patients; disseminated organic neurological symptomatology and endocrine disturbances were additionally identified in some of the patients. There were paroxysmal attacks periodically in the overwhelming majority (68%) of the patients; this correlated with the presence in the EEG of epileptic forms of activity. The patients were divided into two groups on the basis of the character of the EEG. Patients in whom slow alpha waves and waves of the theta range with a "focus" in the central-frontal regions of the cortex were recorded were included in group I (25 individuals). Analysis of the localization of the sources of epileptic activity revealed placement at the midline level in them with marked compactness and displacement of the focus to the right hemisphere. In the patients of group II (15 individuals), slow waves of frontal localization and diffuse beta waves predominated in the EEG in the presence of a reduction in the level of biopotentials. The localization of equivalents of epileptic activity was more diffuse in character and was at the basal level, with a greater representation of the sources of epileptic activity in the left hemisphere.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Rhythmic alpha-activity generators in the human EEG.

This study was designed to locate the neuronal mechanisms of rhythmic activity in the human brain in the alpha-rhythm range using an equivalent dipole model. The experiments approach used here is based on using the "imposed rhythm" phenomenon, whereby a light stimulus flashing with a frequency close to the frequency of the individual alpha rhythm increases its power in the EEG spectrum. The results obtained showed that the activity of the structures generating the alpha rhythm could be differentiated by using a specific photostimulation frequency and were located by constructing a dipole model. Two sources of alpha-rhythm generation were found, located in the thalamic structures of the brain and operating over a narrow-band frequency range with maximum response resonance frequencies of 10.1 and 10.5 Hz.

Adult↗