Cerebral cortex (New York, N.Y. : 1991)
August 1, 2024
Evan Lewis-Healey, Enzo Tagliazucchi, Andrés Canales-Johnson et al.
27 citations
Intentional breathing techniques (breathwork) can induce altered states of consciousness similar to those produced by psychedelics. By tracking subjective experiences moment-by-moment alongside portable EEG recordings across 301 sessions from 14 novice participants, researchers found that psychedelic-like experiences—especially intense bliss—corresponded with increased neural complexity (Lempel-Ziv complexity) and changes in the aperiodic exponent of brain activity, but not with alpha brainwave power. These non-linear neural features map onto both broad positive experiences and specific psychedelic-like states, suggesting breathwork alters consciousness through mechanisms distinct from simple relaxation or meditation.
Journal of Cognitive Neuroscience
December 30, 2025
Evan Lewis-Healey, Carla Pallavicini, Federico Cavanna et al.
4 citations
The psychedelic drug DMT rapidly reorganizes conscious experience and brain activity, but the link between brain dynamics and subjective effects remains unclear. In a blinded, dose-dependent study, 19 participants received 20 mg or 40 mg of DMT. The higher dose produced more intense visual hallucinations and emotional experiences. Electroencephalography data showed that alpha power and permutation entropy best tracked moment-to-moment changes in subjective experience, while Lempel-Ziv complexity—previously thought to be a strong correlate—showed the weakest association. The findings indicate that the relationship between neural complexity and psychedelic phenomenology is less straightforward than hypothesized.
Psychology & Neuroscience
May 26, 2022
Evan Lewis-Healey, Ruben Laukkonen, Michiel van Elk
4 citations
Psilocybin-assisted psychotherapy may treat depression by weakening the connections between symptoms in a complex dynamic network, according to a theoretical model called the Relaxed Symptom Network. Drawing on the Network Theory of Mental Disorders, which views depression as an emergent phenomenon from strong symptom interactions, the authors propose that successful therapy reduces these connections, making patients less vulnerable to developing or relapsing into depression. The article summarizes clinical trials showing antidepressant effects of psilocybin when embedded in psychotherapy, reviews contested mechanisms, and offers practical guidance for integrating network theory into future clinical research.
May 19, 2021
Evan Lewis-Healey, Ruben Laukkonen, Michiel van Elk
3 citations
preprint
Psilocybin-assisted psychotherapy (PAP) shows promise for treating depression, but how it works is debated. The authors propose that depression arises from strong interactions among symptoms in a dynamic network, and that successful PAP weakens these connections, making relapse less likely. They call this the Relaxed Symptom Network hypothesis and argue that applying network theory could improve treatment response and reduce relapse. Practical guidance for integrating this framework into future clinical research with psilocybin is provided.
bioRxiv Preprint Server
December 19, 2024
Evan Lewis-Healey, Carla Pallavicini, Federico Cavanna et al.
1 citation
preprint
A dose of the fast-acting psychedelic DMT rapidly reorganizes conscious experience and brain dynamics, but the link between neural complexity and subjective effects is weaker than previously thought. Nineteen participants received 20 mg or 40 mg of DMT in two sessions. The higher dose produced more extreme visual hallucinations and emotionally intense experiences. Contrary to earlier claims, Lempel-Ziv complexity—a measure of neural signal diversity—was the least strongly associated neural marker of the psychedelic state. The findings suggest the relationship between neural complexity and phenomenology during psychedelic experiences is less clear than originally hypothesized.
bioRxiv
May 4, 2026
Tomás Ariel D’amelio, Tomás Gil Garbagnoli, Jerónimo Rodríguez Cuello et al.
Inhalation of DMT, a serotonergic psychedelic, produces a brief surge in sympathetic nervous system activity—heart rate, skin conductance, and respiration—that closely tracks the intensity of the emotional experience. Nineteen participants received 20 or 40 mg of DMT under a semi-naturalistic blinded design. Higher doses caused heart rate and breathing to increase within the first two minutes, while skin conductance rose only later, indicating a prolonged autonomic response. As the drug's effects waned, feelings of pleasantness and bliss emerged. Combining simple physiological measures with moment-by-moment self-reports offers a way to objectively characterize psychedelic-induced emotional states, which may aid future clinical biomarker research.
Apollo (University of Cambridge)
December 30, 2025
Evan Lewis-Healey, Carla Pallavicini, Federico Cavanna et al.
A dose of the fast-acting psychedelic drug DMT rapidly reorganizes both conscious experience and brain activity. In a blinded, counterbalanced study, 19 participants received either 20 mg or 40 mg of freebase DMT. The higher dose caused more extreme visual hallucinations and emotionally intense experiences. Electroencephalography showed that changes in alpha brainwave power and a measure of signal irregularity (permutation entropy) were most strongly linked to moment-by-moment changes in subjective experience. Surprisingly, a measure of neural signal complexity (Lempel-Ziv complexity), previously thought to be a robust marker of psychedelic states, showed the weakest link to experience. This suggests the connection between brain complexity and conscious experience during psychedelic states is less straightforward than previously assumed.
Neuroscience of consciousness
January 1, 2024
Ruben E Laukkonen, Evan Lewis-Healey, Luca Ghigliotti et al.
A novel multivariate spatial filter called Rhythmic Entrainment Source Separation can extract steady-state visual evoked potentials from EEG data to quantify perceptual switch rates during binocular rivalry without requiring self-reports. This method may be valuable for studying consciousness in contexts where self-reports are problematic or impossible. The analyses also indicate that no-report conditions may affect attention deployment and thereby neural correlates, an important consideration for consciousness research.