[Trace rhythm recruitment by the neurons of the rabbit sensorimotor cortex in old age].

Spectral analysis (ACG and gSP) of the impulse activity of the neurones of the old rabbits sensorimotor cortex allowed to reveal a trace recruitment of the rhythm--CR analogue to time--in after-action f rhythmic stimulation. Connection was established between the number of presented series of periodic electrocutaneous stimulation and expressiveness of the trace rhythm recruitment depending on the animals age. Trace rhythm recruitment took place slower in old animals (54-56 months) than in young ones (up to 1 year), chiefly in 2-3 experimental days after 2-4 series of rhythmic stimulation and was preserved in a small percent of cases the next day after stimulation. In the background activity of a number of neurones an initial periodicity was discovered, which was intensified under the influence of stimulation by another frequency, or the initial rhythm was extinguished, and stimulation rhythm was reproduced. Periodical stimulation in very old animals (66-85 months) practically did not evoke plastic reconstructions of the cortical neurones. Under the influence of the stimulation a non-specific trace increase of the frequency of neurones background activity of the old animals was observed. The revealed characteristics of plastic neurones properties may testify to projected disturbances of mnestic processes at definite age stages of normal aging.