Serotonergic psychedelics temporarily modify information transfer in humans

Area of Science:

• Neuroscience
• Psychopharmacology
• Information Theory

Background:

• Psychedelics profoundly alter consciousness, self-perception, and reality.
• Mechanisms of psychedelics are understood at molecular levels, but global brain dynamics remain unclear.
• Brain imaging reveals altered functional coupling between frontal and parietal regions during acute psychedelic effects.

Purpose of the Study:

• To investigate psychedelic-induced changes in directed information flow within the human brain.
• To measure modifications in brain oscillation connectivity using transfer entropy.
• To explore the relationship between information flow alterations and subjective psychedelic experiences.

Main Methods:

• Ten healthy males with prior psychedelic experience participated.
• Participants received either a placebo or ayahuasca (containing N,N-dimethyltryptamine).
• Directed functional connectivity was assessed using transfer entropy analysis of brain oscillations.

Main Results:

• Significant changes in brain oscillation coupling between anterior and posterior sites were observed.
• Frontal brain regions showed decreased influence over central, parietal, and occipital sites.
• Posterior brain regions increased their influence over anterior sites, correlating with subjective effects and incapacitation.

Conclusions:

• Psychedelics temporarily disrupt neural hierarchies in the human brain.
• Top-down neural control is reduced, while bottom-up information transfer is increased.
• These findings offer insights into the neurobiological underpinnings of psychedelic states.