Neuronal Gap Junctions in Cortical Columns and Nuclei of the Ventral Thalamus of Rats

Abstract

Functional cortical columns and nuclei of the ventral thalamus play a key role in processing of sensory information; therefore, detailed studies on formation of neuron-to-neuron gap junctions in these areas are of great theoretical and practical importance. In the present study, we applied electron-microscopy methods to examine the structure and specific distribution of interneuronal gap junctions in the cortical layer IV and thalamic nuclei, including VPM, RTN, Pom, and VPL. In the cortex, we found more interneuronal gap junctions than in thalamic nuclei. In all structures studied we revealed and described axo-dendritic, dendrodendritic, and “mixed” synapses. We report on the axo-dendritic gap junctions for the first time. It is suggested that this type of contacts plays some functional role in local synchronization of neuronal activity within one ensemble on the presynaptic level.