Dissociations Between the Effects of LSD on Behavior and Raphe Unit Activity in Freely Moving Cats
Science – August 03, 1979
Source: OpenAlex
Summary
Low doses of LSD can trigger significant behavioral changes, even with minimal impact on serotonergic raphe neuron activity. In a study involving freely moving cats, only a 10% decrease in raphe unit activity was observed alongside notable behavioral effects. Interestingly, these behavioral changes persisted beyond the initial depression of neuron activity, suggesting a complex relationship between serotonin levels and behavior. Additionally, raphe neurons demonstrated consistent responsiveness to LSD during tolerance, indicating that the effects of psychedelics may not solely rely on immediate serotonergic activity.
Abstract
The hypothesis that the action of hallucinogenic drugs is mediated by a depression of the activity of brain serotonergic (raphe) neurons was tested by examining the behavioral effects of d -lysergic acid diethylamide (LSD) while studying the activity of raphe neurons in freely moving cats. Although the results provide general support for the hypothesis, there were several important dissociations. (i) Low doses of LSD produced only small decreases in raphe unit activity but significant behavioral changes; (ii) LSD-induced behavioral changes outlasted the depression of raphe unit activity; and (iii) raphe neurons were at least as responsive to LSD during tolerance as they were in the nontolerant condition.