INHIBITORY INTERACTIONS IN AUDITORY THALA MOCORTICAL CIRCUITRY

Crosscorrelation method was used for revealing effective inhibitory in teractions in neural networks containing simultaneously recorded neuro ns from different loci of auditory cortex (A1) and medial geniculate b ody (MGB). It was shown that (i) inhibitory connections were ''diverge nt'', i.e., one neuron in A1 (MGB) depressed activity of neurons in di fferent loci of A1 and MGB simultaneously; (ii) inputs to inhibitory n euron were ''convergent'', i.e., one neuron in A1 (MGB) was excited by neurons from different loci of A1 and MGB simultaneously. There were inhibitory neurons which selectively depressed activity of only one ne ighbouring neuron. The results allow to suggest that the same inhibito ry neuron may be involved in afferent and feedback inhibition. We supp osed that the principles of organization of inhibitory connections in thalamo-cortical networks underlie the observed exceptions to mapping (tonotopic) principle of organization of receptive fields of A1 and MG B.