Morphology of rats AV thalamic nucleus in light and electron microscopy

The structure of the rat's antero-ventral thalamic (AVTh) nucleus has been investigated in order to provide background information for the accompanying study in which an attempt was made to identify the synaptic terminals of the different afferent fiber systems to this nucleus by means of both EM autoradiography and the EM degeneration techniques. Nissl stained sections showed that the rat's AVTh nucleus contains mainly relatively light staining neurons which in Golgi material were found to possess tufted dendrites. In EM material three types of synaptic terminals were found which showed a topical distribution over the neuronal surface. Soma and stem dendrites carry a limited number of terminal with symmetrical synapses and flattened vesiclesmproximal dendrites carry mainly large asymmetrical synaptic terminals while distal dendrites are crowded with small asymmetrical synaptic terminals.