Early and Contemporary Human Neuroimaging Studies of Serotonergic Psychedelics

Serotonergic psychedelics alter conscious awareness, perception, mood, emotion, and cognition, but their effects resist simple classification like stimulant or sedative. Their defining feature is temporarily inducing an altered state of consciousness. Because only humans can explicitly report conscious experiences, studying these compounds requires non-invasive neuroimaging techniques in healthy subjects. This review examines how neuroimaging has been applied to investigate the neural correlates of altered consciousness caused by serotonergic psychedelics.

Study at a glance

Abstract

Serotonergic psychedelics are known to elicit changes in conscious awareness, including perception of the environment and the self, as well as in mood, emotion and different aspects of cognition (Nichols, 2016). The effect of these compounds is complex and resists a straightforward classification that is useful for other drugs, such as “stimulants” or “sedatives”. While the effects of certain psychedelics do have a stimulant dimension, their defining characteristic is the capacity to temporarily induce a state of altered consciousness. Because of this, the study of psychedelics cannot be based only on animal models, since humans are alone in their capacity to explicitly report the contents of their conscious awareness. Psychedelic research with healthy human subjects necessitates techniques for the non-invasive recording of brain activity or its physiological and metabolic correlates. These techniques are referred to as “neuroimaging”, and here we review their application in the study of the neural correlates of altered consciousness induced by serotonergic psychedelics.