[Plastic reorganization of the activity of sensorimotor cortex neurons during elaboration of a cellular analog of a temporary connection].

A study of plastic reorganizations of neuronal responses in the rabbit sensorimotor cortex was made on a cellular analogue of conditioned connection where stimulation of the ventrobasal thalamic complex (VBC) was used as a conditioned stimulus, while polarization of the cell through a recording microelectrode, as an unconditioned one. The responses of 60% of the studied neurones to the stimulation of the VBC showed significant plastic changes after the pairing of thalamic stimulation with polarization. The changes obtained met the criteria of identification of conditioned reactions. One of the possible mechanisms of the recorded plastic reorganizations of neuronal reactions consists in a selective increase in the effectiveness of excitatory synapses, whose subthreshold activation coincided with the cell activation. These data may be regarded as manifestation of a hypothetic reverse influence of neuronal discharges on the effectiveness of the synaptic transmission.