Asunto(s)
Ritmo alfa , Atención/fisiología , Lateralidad Funcional/fisiología , Adulto , Femenino , Humanos , MasculinoAsunto(s)
Atención/fisiología , Encéfalo/fisiología , Adulto , Ritmo alfa , Electrofisiología , Femenino , Humanos , Masculino , Estimulación Física/métodos , Valores de ReferenciaAsunto(s)
Ritmo alfa , Encéfalo/fisiología , Adulto , Percepción Auditiva , Humanos , Aprendizaje , Percepción VisualRESUMEN
Degree of manifestation and synchronization of rhythmic alpha-range components in various cortical areas was studied in healthy adult subjects in conditions of controlled computer experiment by spectral-correlation method of EEG analysis during directed attention previous to discrimination of tactile, auditory and visual stimuli. The obtained results show that in preparation for discrimination of heteromodal stimuli, specific reconstructions take place of alpha-range electrical activity determined by signal modality. These changes are expressed in a local increase of the degree of synchronization of alpha oscillations in those projection and associative brain areas which are connected with the analysis of the given stimuli. Functional significance of these reconstructions is seen in the fact that they are significantly more expressed at correct recognition. A hypothesis is suggested about participation of the alpha-range in neurophysiological mechanisms of directed attention.
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Ritmo alfa , Atención/fisiología , Corteza Cerebral/fisiología , Adulto , Humanos , Estimulación LuminosaRESUMEN
In adult healthy right-handed subjects, the expression and degree of synchronization of the EEG alpha-range rhythmic components in different areas of the right and left hemispheres, were studied in a state of quiet wakefulness and during solving of verbal and spatial tasks presented in the visual field. The EEG of quiet wakefulness was characterized by different distribution of the alpha-range rhythmic components in the right and left hemispheres; in the right hemisphere low frequencies (7.5-10.5 c/s) were more expressed and more coherent; in the left one--the high frequencies (10.5-13.5 c/s). The solving of tasks was accompanied--along with a decrease of the whole alpha-range power spectra both in the right and the left hemispheres--by a local increase of synchronization of certain components of this range; the increase was specific to the hemisphere and the kind of task. The increase of synchronization of low-frequency components was observed in the right hemisphere during solving of the spatial task and that of the high-frequency components was noticed in the left hemisphere during solving of the verbal task. On the basis of the data on hemispheric specificity of electric activity synchronization of the alpha-rhythm, a suggestion is made about a different character of the functional integration of the structures of the right and left hemispheres in the process of solving of spatial and verbal tasks.