Effects of LSD on Receptive Fields of Single Cells in the Lateral Geniculate Nucleus of the Cat

Abstract

SMALL doses (∼ 100 µg) of lysergic acid diethylamide (LSD) taken orally cause hallucinations and distortions of visual perception in man¹. The latter effects suggest that LSD disturbs normal integrative functions in the visual pathways. It is known that transmission through the visual pathways is depressed by the drug, for small doses (15–30 µg/kg) given parenterally depress the response of the cat lateral geniculate nucleus (LGN) to shocks applied to the optic nerve^2,3. Similar doses have no effect on the responses of the visual cortex to electrical stimulation of the optic radiation. These results suggest a relatively selective influence of LSD on the LGN, which is known to be involved in the integration of signals passing to the visual cortex from the optic tract⁴. This function can be analysed by studying the receptive fields of single cells in the nucleus. We have therefore studied the effects of LSD on the spontaneous and evoked activity of cells in the LGN of cats, and present a brief account of some of our findings.