Linked activity of neurons in the sensorimotor cortex of the rabbit in the state of a defensive dominant and "animal hypnosis".

A cryptic focus of excitation (a dominant focus) was created in the brains of rabbits by threshold stimulation of the left limb with a current at a frequency of 0.5 Hz. After creation of a focus, there were equal probabilities of detecting pairs of neurons whose linked activity was dominated by a 2-sec rhythm in the sensorimotor cortex of both the right and left hemispheres (29.3% and 32.4%, respectively). When animals were placed in "animal hypnosis," the total proportion of neuron pairs whose activity was dominated by the rhythm created by establishment of the dominant decreased significantly only in the right hemisphere (21%). After exiting the state of animal hypnosis, the proportion of neurons in the cortex of the right hemisphere whose activity was dominated by the 2-sec rhythm increased significantly if the neurons in the pair were close-lying but decreased significantly if the neurons in the pair were mutually distant. No such changes after hypnotization were seen in the cortex of the left hemisphere. In both the right and left hemispheres, dominance of the 2-sec rhythm in the activity of pairs of neurons was seen significantly more frequently when cross-correlation histograms were constructed by analyzing cells in relation to the spike activity of neurons generating spikes of the lowest (right hemisphere) or lowest and intermediate (left hemisphere) amplitude on neurograms of multineuron activity.