Electrophysiological studies of d-lysergic acid diethylamide in the visual system

Experiments involving the use of LSD and observing its effects on neurons involved in the processing of visual information are reviewed. These studies typically involved either intravenous or iontophoretic application of the compound. Both modes of application appeared to block the optic afferent synapse at the level of the dorsal lateral geniculate nucleus and to alter the evoked activity of visual cortical neurons. Increasing the dose of LSD regardless of the manner in which it was applied tended to produce depression of both spontaneous and visually driven activity. The receptive field properties of the neurons at all levels of the visual system appear to remain intact after LSD despite changes in spontaneous activity. The effect of LSD on non-specific afferents to the dorsal lateral geniculate nucleus is depicted in relationship to two of the different kind of relay cells located in this structure. Data on LSD interaction with the effects of midbrain stimulation on “X” and “Y” neurons is presented.