N. N. Karamysheva

Correlations between Neuron Activity in the Sensorimotor Cortex of the Right and Left Hemispheres in Rabbits during a Defensive Dominant and “Animal Hypnosis”

A latent focus of excitation with a rhythmic nature (a defensive dominant focus) was created in the CNS of rabbits. The focus was formed by threshold electrocutaneous stimulation of the left forelimb using series of impulses consisting of 15–20 stimuli with interstimulus intervals of 2 sec. The linked activity of cells in the sensorimotor cortex of the right and left hemispheres was analyzed. When cross-correlation histograms of the spike activity of sensorimotor cortex neurons in the left hemisphere were constructed and analyzed in relation to spikes of high and intermediate amplitude recorded in the right hemisphere, the linked activity of 15% and 23% of neuron pairs, respectively, showed predominance of a rhythm equal or close to the stimulation rhythm used to form the dominant focus. When the appearance times of spikes from neurons in the sensorimotor cortex of the right hemisphere were analyzed in relation to spikes of high and intermediate amplitude recorded in the cortex of the left hemisphere, predominance of 2-sec rhythms was seen in the linked activity of only 3% and 10% of neuron pairs, respectively. After induction of “animal hypnosis,” differences between the hemispheres in relation to this measure leveled out.

Solution of Mathematical Logical Problems in a Sensory Enriched Environment (classical music)

Accompaniment of the solution of mathematical logical problems with classical music at levels of 35 and 65 dB led to decreases in problem solution times. Louder music (85 dB) had no significant influence on the problem solution process. Solution of mathematical logical problems without musical accompaniment led to increases in the coherence of potentials in the beta1, beta2, and gamma frequency bands in the occipital areas of the cortex, with a predominance in the left hemisphere. EEG coherence decreased in the frontal area of the cortex. Music decreasing problem solution time induced increases in left-sided EEG asymmetry. Accompaniment of problem solution by classical music increased both intrahemisphere and interhemisphere coherence of potentials in the frontal areas of the cortex. Use of louder music (85 dB) to accompany problem solution induced right-sided EEG asymmetry, and foci of coherence links also often appeared on the EEG of the temporal area of the right hemisphere.

Neuron Activity before Behavioral Reactions and before Missed Reactions in a Defensive Dominant

The network relationships of neocortical neurons in rabbits with a defensive dominant in the CNS were studied in conditions of calm waking and during the intervals between presentations of light stimuli testing the dominant. Statistical analysis of spike trains extracted from multineuron traces allowed detection of differences in the functional organization of neurons in the excitation focus (sensorimotor cortex) and the representation area of the stimulus testing it (visual cortex) in calm waking before triggering of effector reactions and before missed reactions. These experiments yielded data on the different roles of sensorimotor cortex cells responding and not responding to light stimuli in the network activity of the areas of cortex studied.

Correlation between the Activities of Sensorimotor and Visual Cortex Neurons during Formation of a Cryptic Focus of Excitation (a defensive dominant) in the Cortical Representation of the Forelimb in Rabbits

Cross-correlation analysis was used to study the interaction of neurons in the sensorimotor and visual areas of the cortex in rabbits with cryptic foci of excitation formed in the representation area of the forelimb; the role of sensorimotor cortex neurons responding to light in this interaction was also studied. The results showed that in rabbits with cryptic foci of excitation, sensorimotor cortex neurons responding to light stimuli showed correlational relationships with cells in the visual cortex significantly more frequently than neurons not responding to light, while visual cortex neurons significantly more frequently formed correlational relationships with sensorimotor cortex neurons not responding to the stimulus.