Chapter 10 The ventro-medial medullary projections to spinal motoneurons: ultrastructure, transmitters and functional aspects

Abstract

Publisher Summary This chapter considers the ventro-medial medullary projections to spinal motoneurons in detail with respect to their ultrastructure, transmitters and function. In general terms, the ventro-medial medulla comprises the area ranging from the caudal part of the inferior olive to the caudal part of the trapezoid body. At the level of the inferior olive it also comprises the nucleus raphe obscurus, the ventral part of the nucleus raphe pallidus and the area immediately overlying the inferior olive and immediately laterals to it. More rostrally it comprises the nucleus raphe magnus and laterally adjacent areas up to the medial border of the facial nucleus. In the rat, according to the nomenclature of Andrezik and Beitz, the ventro-medial medulla includes the ventral part of the paramedian reticular nucleus, the gigantocellular nucleus-ventral part and the ventro-medial part of the paragigantocellular nucleus at the level of the inferior olive. It is important to note that the more dorsally located gigantocellular nucleus, which comprises many spinal projecting cells, including giant cells, is not considered part of the ventro-medial medulla.