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September 1959

Effects of LSD on Cortex of Cat Correlated with Changes in Vital Signs

Author Affiliations

From the Division of Neurological Surgery, The Johns Hopkins University, School of Medicine.
Present address (Dr. Finney): U. S. Naval Hospital, Chelsea, Mass.
Presented in part before the American Physiological Society, London, Ont., Canada, September, 1958.

AMA Arch Neurol. 1959;1(3):269-281. doi:10.1001/archneur.1959.03840030027003

Introduction  In a previous report15 it was demonstrated that large doses of lysergic acid diethylamide (LSD) had no consistent effect on primary sensory evoked potentials in the cortex of the cat. However, in a recent publication Purpura21 reported qualitative differences in the effect of LSD on cortical evoked potentials and postulated that these were due to anatomical differences in the termination of afferents in the cortex, some ending on soma and others on dendrites. Sensory afferents end primarily on the soma of cortical neurons.In contrast, direct electrical stimulation of the cortex produces a predominantly surface-negative wave, which is generally considered to represent the activity of apical dendrites.5,8,10 Furthermore, it is also thought to be a postsynaptic potential analogous to the postsynaptic potential of motoneurons in the spinal cord.9 Also, anatomical evidence has been advanced to indicate that callosal fibers terminate primarily on dendrites or as