[Neuronal activity of the caudate nucleus and centrum medianum of the thalamus in the cat during formation of an instrumental defensive conditioned reflex].

Implanted tungsten microelectrodes were used for studying the neuronal activity of CN and MC at initial stage of formation of instrumental defensive behaviour. The linear correlation coefficient was not above +/- 0.15 during recording of the background impulse activity before presentation of the positive stimulus to the animal or during its presentation not more than 100 times. In the course of formation of the instrumental reflex the correlation coefficient increased up to +/- 0.3 for 19 cells and up to +/- 0.31--+/- 0.56 for 9 cells. Inhibitory conditioned reactions were characteristic of 34 CN neurones (out of 56) and responses of 42 MC neurones (out of 51) had an activating form. Reactions of both structures were of tonic character with most pronounced changes at the start of the conditioned signal. In dynamics of instrumental behaviour formation, the intensity correlation coefficient of CN and MC neurones reactions recorded simultaneously, increased.