Anticholinergic Hallucinosis. I. Effect of Atropine and JB-329 on “Caudate Spindle” Phenomena and Electrical Activity of Cat Hippocampus

Abstract

The neurophysiologic mechanisms of hallucinations have been the subject of many investigations. Almost all known hallucinogens have been used to induce changes in the electrical activity of the brains of the cat, dog, and man [1–6]. In those investigations where hippocampal activity was studied, there were consistent alterations of the spontaneous electrical potentials [7, 8]. In a specific afferent system (visual), there have been, however, conflicting reports of the effects of LSD on the primary and secondary components of the evoked potential [1–3]. Fink [9] has postulated an involvement of the reticular system in hallucinosis; however, he utilized indirect methods of measuring reticular involvement. In spite of the many excellent studies, it is apparent that we still have an incomplete picture of the changes occurring in the many systems of the brain. With these data, therefore, it seems premature to implicate any one system as the mediator of hallucinations. Since further investigative efforts seemed desirable, the authors undertook to carry out a more complete investigation of the effects of two anticholinergic hallucinogens on the reticular system, hippocampus, and visual system. We attempted to evaluate the relative involvement of these systems and to determine the specific role of both the mesencephalic and thalamic reticular system.