Consciousness is not fully understood by scientists, but it is known that psychedelic drugs alter the state of consciousness. Three psychedelic drugs (LSD, ketamine, and psilocybin) were found to enhance consciousness as measured by magnetoencephalogram neuroimaging and signal diversity.
Most of us think of consciousness, our perceptions, thoughts, and feelings, as the state we are in when we are awake. However, scientists still do not have a full understanding of the brain mechanisms underlying consciousness. Research remains focused on the difference between conscious level and conscious content, and how the two are related. Conscious level refers to how conscious one is, while conscious content encompasses what one is actually conscious of during the state of consciousness. Because psychedelic drugs affect conscious experiences, they provide a useful tool for studying consciousness. Additionally, they do not cause a loss of consciousness, but instead seem to alter conscious content. Schartner and colleagues aimed to examine whether consciousness would be altered following administration of psychedelic drugs, in order to shed further light on consciousness and the state of consciousness during psychedelic drug use. They published their findings in Scientific Reports.
Consciousness can be studied using magnetoencephalogram (MEG) and electroencephalogram (EEG) techniques to measure neural signal diversity. The authors expected that three different psychedelic drugs (LSD, ketamine, and psilocybin) would produce greater signal diversity scores compared to normal consciousness levels. In order to assess this, they analyzed MEG recordings using specific signal diversity measures. Measurements were collected in healthy participants who were administered either a psychedelic drug or placebo intravenously. The participants were also asked to fill out a questionnaire to evaluate their psychedelic experiences.
The authors found that among the psychedelic drugs tested, there was an increase in signal diversity in the psychedelic state compared to placebo. These results were supported by the questionnaire results. For example, common answers from participants administered psychedelic drugs included phrases such as: “my imagination was extremely vivid” and “I felt like I was floating”. This is the first report indicating that signal diversity measures related to consciousness are also associated with the psychedelic state. The results also suggest that signal diversity measures may be used to study comparisons between conscious level and conscious content. Furthermore, the results support the notion that increases in both conscious level and conscious content are related. Not only do these findings shed further light on the state of consciousness during psychedelic drug administration, but they also broaden our understanding of basic wakeful consciousness.
Written By: Liana Merrill, PhD