An Investigation On The Projection Pathway From The Trigeminal Mesencephalic Nucleus To The Thalamus In The Rat

The purpose of the present paper is to study the ultrastructure of the neuronal perikarya, mophological basis of the electrotonic coupling, the type of the synapses on the perikaryal surface, and the kinds of neural active substance contained in the presynaptic terminals in the trigeminal mesencephalic nucleus (Vme).In the first series of experiments, 4 rats were used to examine the ultrastructure of Vme. It was found that , spines of various size, the larger ones measured 4 μm or longer, stouted on the perikaryal surface. Because there was a similarity of the altrastra(?)ture between spines and (?)rites and the spines were also found receiving synapse from axonal terminal, it was suggested that these perikaryal spines posess a dendrite-like function. On the perikaryal surface axo-somatic synapses...