Spatial synchronization of rabbit brain biopotentials upon repeated electrical stimulation of the cortex]

A study was made on 23 rabbits of the degree of spatial synchronization in response to repeated electrical stimulations of one or simultaneously two cortical areas: the sensorimotor or visual, or simultaneously the sensorimotor and visual, or sensorimotor and precentral respectively. Enhancement of the synchronization induced by the stimulation, globally spread over the entire cortex and was followed by its decrease. However, in the two directly stimulated areas of the cortex, the similarity of bioelectrical oscillations persisted for a long time, which testifies to the establishment of selective relations between them.     

The reflection of emotional tension in the spatial synchronization of the biopotentials in the human brain

In organization of spatial synchronization of bioelectrical activity of the cerebral cortex emotions can play both the role of intensifier and disorganizer of this process. Emotions raise the level of spatial synchronization in situation of active work and may decrease initial background values of synchronization if they organize passive-defensive state.     

Structure of the field of cerebral biopotentials and the latent period of the human motor response

An investigation was made into the statistical interconnection between the latency of human conditioned motor reaction to a flash and the spatial distribution of EEG correlation coefficients of eight cerebral areas in 10-second epoch preceding the stimuli. The greatest similarity of latency variations was observed with changes in the correlation relationships between EEG of the occipital, frontal and central areas of the hemisphere, contralateral to the reacting hand. Analysis of the structure of the brain biopotential field has shown that the probability of a more rapid reaction is greater if in the pre-stimulatory period there is a spatially coherent alpha-rhythm with nearly contraphasic correlations of oscillations in the frontal and occipital brain areas.     

Features of the organization of biopotentials of a cerebral cortex and visceral status at the person at neurotic depression

Researches are spent on 20 patients with various clinical variants of neurotic depression. The regional organization of bioelectric activity of a brain by a method cross-correlation and coherent analysises was studied. Vegetovisceral status was studied by auricular criotest (measuring of cold sensibility of auricular points). It is shown, that the clinical picture of neurotic depression finds reflectance in frame of regional organization EEG. Regional organization EEG is modified depending on a degree of manifestation of the most neurotic depression and concomitant syndromes of alarm and an asthenia. In bunch with a depressive syndrome without concomitant asthenic and disturbing exhibitings the maximum changes are taped in the right frontotemporal range--left posttemporal ranges. In bunch where along with depression the alarm--depression cross-correlation and coherent communications frontotemporal ranges of both hemispheres was taped, strongly pronounced rising cross-correlation attitudes in right occipital ranges. In bunch where depressive and disturbing syndromes were combined with the expressed asthenic exhibitings, depression cross-correlation and coherent communications in frontotemporal ranges of both hemispheres was observed. The clinic of neurotic infringements finds reflection in a specific picture of variations of the spatial organization of electric activity of a brain and in variations of parameters of the vegetovisceral status. Realization of negative emotional conditions at the person is accompanied by variations visceral functions. Thus variations in the central brain structures cover zones of representation of emotional reactions and the zones connected with cortical representation visceral functions. The minimal central regulation, even insignificant central variations can cause vegetovisceral dysfunctions.     

A correlational analysis of electroencephalograms based on the modeling of biopotentials of the cerebral cortex

Our previous study on the quantitative nonlinear analysis of integral equations of the averaged membrane potentials in excitatory (the EEG analogue) and inhibitory neurons of the neocortex has shown that the characteristic equation has a set of oscillating solutions with negative decrements in the stability region. We have shown that an electroencephalogram can be represented as a convolution of harmonic functions with negative decrements and discrete (uniformly discontinuous) white Gaussian noise. We have suggested methods of decrement calculation in encephalograms using correlation functions and tested them on both modeled processes with preset parameters and actual encephalograms of rats and mice. Investigation of decrements and amplitude-frequency parameters potentially increases the capacity of spectral correlation analysis of electroencephalograms and expands the results of mathematical processing of brain signals.