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Effects of drugs on “augmenting/reducing” in averaged visual evoked responses in man

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Summary

The averaged visual evoked response (VER) amplitude in some subjects at the greatest depths of modulation of sine wave light is the same or less than at lesser depths of modulation. This phenomenon is referred to as “reducing” and is measured by computing the slope of VER amplitudes as a function of the four greatest modulations. Previous studies reported that “reducing” varies between test and retest sessions, possibly due to changes in the subjects' level of arousal. In order to test this hypothesis, various drugs were employed to alter level of arousal. It was found that the two depressants (sodium pentobarbital and ethyl alcohol) both significantly decreased the slope of the VER amplitude at the four highest depths of modulation, i.e. subjects “reduce” more. Stimulants (methamphetamine and caffeine) and placebo, on the other hand, had no effect on the slopes. The lack of change in slope after the stimulants is discussed and possible explanations are advanced. It is concluded that level of arousal is one factor in determining the “augmenting/reducing” level of subjects.

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Authors and Affiliations

  1. Department of Pharmacology, University of California, Medical Center, San Francisco, California

    Bert Spilker

  2. California Department of Mental Hygiene, Langley Porter Neuropsychiatric Institute, San Francisco, California

    Enoch Callaway

  3. Department of Pharmacology Therapeutics Research Division, The Pfizer Group, Sandwich, Kent, England

    Bert Spilker

Authors
  1. Bert Spilker
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  2. Enoch Callaway
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Additional information

Supported by PHS Training Grant No. NB-5270 from N.I.H., Office of Naval Research Contract NONR 2931(00), National Institutes of Health Interdisciplinary Training Program MH 7082, California Department of Mental Hygiene grant 67-1-49. Reproduction in whole or in part is permitted for purposes of the United States Government.

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Spilker, B., Callaway, E. Effects of drugs on “augmenting/reducing” in averaged visual evoked responses in man. Psychopharmacologia 15, 116–124 (1969). https://doi.org/10.1007/BF00407044

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  • DOI: https://doi.org/10.1007/BF00407044

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