Brainstem Influences on Forebrain Processes, Including Memory
Robert W. Doty University of Rochester School of Medicine and Dentistry
Although the human cerebral cortex defines the pinnacle of neuronal evolution, it remains irretrievably inoperative without input from the pervasive machinery of its phylogenetic predecessors, the monaminergic and cholinergic nuclei of the brainstem. This chapter briefly and selectively reviews the history of how this fact was discovered, updates and supplements an earlier synopsis ( Doty, 1989) of various features of these rostrally projecting brainstem systems, and, from work with which I have been associated over the past couple of decades, provides a few examples reflecting operation of these brainstem processes.
Hans Berger's hard-won discovery (see Jung, 1963) that the electrical activity of the human brain and its attendant fluctuations with mental and physical state could be recorded from the scalp immediately broadened the purview of electrophysiology. Advances in instrumentation soon significantly enhanced the feasibility of such studies. In a trail-blazing series of experiments, Bremer ( 1935) turned attention decisively to the fact that the forebrain deprived of mesencephalic input yielded only the electrical signs of sleep. It was not, however, until after World War II that Moruzzi and Magoun ( 1949) made the decisive demonstration that moderate, unilateral electrical stimulation in the midbrain evoked behav-