Effects of LSD-25 on the EEG and Photic Evoked Responses
Archives of General Psychiatry – April 01, 1966
Source: OpenAlex
Summary
Lysergic acid diethylamide (LSD) significantly alters brain activity, evidenced by changes in electroencephalography (EEG). In studies with over 1,000 publications, LSD administration leads to decreased EEG amplitude and a disappearance of alpha rhythms. Specifically, Gastaut reported an increase in average alpha frequencies ranging from 0.5 to 4 cycles per second. Additionally, Grey Walter noted a rise in alpha frequency from 11.6 cps. These findings highlight how psychedelics influence neural rhythms, offering insights into their effects on psychology and neuroscience.
Abstract
SINCE the accidental discovery of the Psychosomimetic properties of Lysergic acid diethylamide (LSD-25) by Stoll,1in 1947, a great amount of work has been carried out to elucidate the behavioral effects and pathophysiological mechanisms of action of this substance. The literature on this topic is steadily growing and contains now more than 1,000 publications.2 There are several studies available that report on the electroencephalographic changes resulting from LSD administration to humans as seen by surface recordings3-9and there are also some observations on changes in the human depth electrogram.10-13It is generally agreed that the amplitude of the EEG decreases, α-rhythms tend to disappear and the tracings become of the lowvoltage fast or desynchronized type. Gastaut4reported that the average α-frequencies are increased by 0.5 to 4 cycles per second (cps) and Grey Walter7noted an increase from 11.6 to