Electroencephalographic Effects of Intraventricular 5‐HT and LSD in the Cat

Publisher Website
Google Scholar
Abstract
An eeg study of the effects, in the brain of the immobilized conscious cat, of intraventricular injections of 5-HT and lysergic acid diethylamide (LSD) reveals the following: The cortical eeg effects, desynchrony with 5-HT and spindles with LSD, give little indication of more profound changes occurring in subcortical regions. Both 5-HT and LSD characteristically depress the amplitude of eeg activity in medial hypothalamic and thalamic nuclei and stimulate the bulbar reticular formation. LSD evokes a high amplitude 50/second rhythm in the pallidum, putamen, amygdala and their projection systems, a change which roughly parallels in time the known duration of sham rage behavior from a similar dosage of the drug. 5-HT retards the eeg activity of the same regions generally to an 8-12/second alpha rhythm, and again the temporal aspect of the changes correlates well with the known duration of lethargic behavior evoked by the drug. Doses of LSD which temporarily reverse the longer lasting behavioral lethargic effects of 5-HT similarly antagonize briefly the 5-HT effects on the eeg activity of pallidum, putamen and amygdala. It is suggested that "LSD-induced" high-amplitude bursts of eeg activity in certain relay nuclei of the thalamus may contribute to aberrancies of sensation.