The reactivity and interaction of neurons of the cerebral cortex of rats in the presence of the microiontophoretic action of acetylcholine in a model negative learning situation.

The activity of 46 pairs of neurons in the sensorimotor cortex of the brain of rats during multiple (up to 60) brief microiontophoretic applications of acetylcholine (ACh) was investigated by means of the method of multicellular recording, with subsequent division into separate impulse streams. It was demonstrated that neurons with high-amplitude spikes have a lower average frequency of discharges in comparison with low-amplitude [neurons]. It was established that cells located adjacent to one another exhibit responses in 63% of cases which are similar in their component makeup; the majority of these responses are inhibitory-excitatory and excitatory. Analysis of the dynamics of the structure of the cross-interval histograms plotted for pairs of cells on the basis of the data of their initial activity, as well as activity in the baseline, and upon termination of the action of ACh, attest to the relative invariability of the excitatory connections between the cells and a possibility of some increase in the efficiency of the inhibitory connections under the conditions of the manifestation of the dynamics of responses to ACh of habituation type by one of the cells.