BULBAR RETICULAR FORMATION AND TREMOR

Abstract

THE TERM tremor denotes rhythmic alternating movements of a part of the body, such as might result from rhythmic contraction and relaxation of groups of muscles or alternating contraction and relaxation of antagonistic muscles at a joint. Its frequency has been variously described as between 3 and 24 per second.¹The occurrence of such rhythmic movements in human disease was first described by Parkinson²in 1817, and since then it has repeatedly been shown that the pathologic changes associated with paralysis agitans are multiple and usually include the zona compacta of the substantia nigra, the globus pallidus, and the ansa lenticularis. Other regions sometimes involved include the neocortex, caudate nucleus, putamen, nucleus amygdalae, zona incerta, Forel fields H-1 and H-2, thalamus, hypothalamus, zona reticularis of the substantia nigra (Soemmerring's ganglion), corpus subthalamicum, mamillary bodies, and other structures of the midbrain, as well as the pons and medulla.³