Skip to content

Yann Harel

3 papers in the library · 25 citations · publishing 2023-2026

Papers

Autonomic nervous system modulation during self-induced non-ordinary states of consciousness

Scientific Reports September 22, 2023 Victor Oswald, Audrey Vanhaudenhuyse, Jitka Annen et al. 24 citations

Self-induced cognitive trance (SICT) is a voluntary non-ordinary state of consciousness involving narrowed awareness, hyper-focused immersion, and altered perception. This study examined autonomic nervous system changes during SICT by measuring heart rate variability and respiration rate variability in 25 proficient participants across three conditions: resting state, SICT, and a mental imagery task. During SICT, participants showed increased heart rate, decreased high-frequency heart rate variability, and specific increases in respiratory amplitude, phase ratio, and respiration rate variability compared to control conditions. These findings suggest SICT is associated with reduced parasympathetic activity, indicating a hyperarousal state of the autonomic nervous system.

LSD Reconfigures Cortical Dynamics Through Faster Brain Rhythms and Increased Fractal Dimension

bioRxiv (Cold Spring Harbor Laboratory) January 29, 2026 Venkatesh Subramani, Timothy Nest, Annalisa Pascarella et al. 1 citation

LSD alters brain activity by increasing alpha and beta brain-wave frequencies while genuinely reducing oscillatory power, with these effects showing distinct cortical patterns. The drug also flattens the aperiodic 1/f spectral slope and increases neural signal fractality and complexity, particularly in sensory, language, emotion, and imagery-related networks, while sparing motor cortex. Machine learning identified peak-frequency shifts, aperiodic parameters, and complexity measures as key discriminators of the psychedelic state. Music did not amplify these neural signatures and showed a trend toward attenuation. These findings provide a comprehensive account of how LSD reorganizes large-scale human brain dynamics.

LSD Relaxes Structural Constraints on Brain Dynamics and Default Mode Decoupling Tracks Ego Dissolution

bioRxiv (Cold Spring Harbor Laboratory) March 5, 2026 Venkatesh Subramani, Annalisa Pascarella, Jérémy Brunel et al.

Lysergic acid diethylamide (LSD) loosens the brain's usual alignment between anatomical structure and neural activity in a frequency-dependent way. Low-frequency brain waves (theta, alpha, beta) become less constrained by the structural connectome, indicating a global relaxation of large-scale dynamics. High-frequency gamma activity shows selective reorganization rather than uniform disruption. Greater gamma-band decoupling within core default-mode network regions predicts the intensity of ego dissolution across individuals. LSD does not cause indiscriminate disintegration but drives system-specific rebalancing: visual and attentional systems decouple while auditory networks strengthen coupling. These findings suggest psychedelic states emerge from frequency-dependent relaxation of structural constraints, with default-mode reorganization as a neural correlate of ego dissolution.