The Limbic System ("Visceral Brain") in Relation to Central Gray and Reticulum of the Brain Stem

Abstract

Summary The limbic system has been defined, and a number of anatomical details have been briefly considered. Reference has been made to the body of evidence that has shown this system to be fundamentally implicated in emotional and viscerosomatic functions. Attention has been directed to the unexplained similarity of some of the psychiatric aberrations seen in cases of encephalitis lethargica and in patients with epilepsy secondary to lesions in or neighboring the frontotemporal portion of the limbic cortex. A possible explanation has been suggested by an inferred interplay between limbic structures and a circumscribed region of the brain stem that von Economo, on the basis of his pathological study of encephalitis lethargica, believed to be of vital significance in emotional processes. The region he delineated includes central gray and reticulum and lies in contiguous parts of the diencephalon and midbrain. Behavioral and electrophysiological observations have been described which offer supporting evidence of the interdependence of limbic structures and the region delineated by von Economo in emotional processes. Some of the psychological and psychiatric implications of these studies have been considered.