Drug action on the electrical activity of the hippocampus.

Publisher Summary This chapter reviews the actions of drugs on the electrical activity of the hippocampus, excluding the actions of drugs on evoked potentials and evoked seizure discharges. The primary discussion in the chapter is related to the drug-induced changes of the hippocampus activity. There is a short section on the spontaneous electrical activity of the hippocampus because knowledge of the normal activity is essential for understanding its drug-induced changes. One of the main advantages of the hippocampus as a tool in neurophysiological and neuropharmacological investigations is the simple and relatively uncomplicated structure of this part of the cortex. Few other brain areas have such a simple structure, one of the exceptions being the prepyriform cortex, which is composed of a single sheet of cells. The simple and well-organized structure of the hippocampus is responsible for its simple pattern of electrical activity, the so-called “theta rhythm,” which appears in the hippocampus under certain experimental conditions. The hippocampus is connected by afferent and efferent pathways with many other brain areas and, therefore, a drug-induced change of hippocampal activity does not necessarily indicate a drug action on the hippocampus itself.