[Effect of stimulation of the mediodorsal nucleus of the thalamus on the synchronous flow of cortical electrical processes].

It was shown in chronic experiments on rabbits that stimulation of the mediodorsal thalamic nucleus brings about, as a rule, en enhancement of amplitudes of the spatially-synchronous cortical theta-rhythm and a decreased frequency of its oscillations. Analysis of the phenomenon by means of a simple mathematical models shows that such a connection between amplitude and frequency EEG parameters may be accounted for by the existence of two-way cyclic interactions between the cortex and the thalamus, forming a closed contour of a feedback connection. The capacity of the mediodorsal thalamic nucleus to influence the synchroneity of cortical electrical processes is compared with published data on its role in conditioned activity.