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.
bioRxiv Preprint Server
April 22, 2026
Nicolás Bruno, Federico Cavanna, Federico Zamberlán et al.
preprint
Spontaneous thoughts make up most of everyday inner experience, but studying them is difficult because traditional methods disrupt the natural flow of thinking or introduce motor artifacts. An alternative approach combined delayed verbal retrospective free reports with automated ratings from large language models. Twenty-two participants performed an eyes-closed free-thinking task, and their reports were evaluated on ten dimensions by four LLMs and human raters. Machine-learning models trained on EEG features achieved above-chance accuracy for predicting emotional valence. LLMs showed higher inter-rater agreement than humans, supporting their use for scalable annotation and suggesting that affective dimensions of spontaneous thoughts can be decoded from brain activity.
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
December 27, 2025
Yayla A Ilksoy, Alethia de la Fuente, Jacobo Sitt et al.
In a backward masking task, participants received transcranial alternating current stimulation (tACS) at 20 Hz or 40 Hz to test whether beta- or gamma-band oscillations causally influence conscious and unconscious visual perception. Contrary to expectations, 20 Hz-tACS selectively impaired objective visibility (correct categorization of masked targets) but not subjective visibility (self-reported conscious perception). 40 Hz-tACS showed no effect. Local beta power increased after 20 Hz-tACS, but inter-areal beta synchrony may have been disrupted. The findings suggest a potential causal role for beta-band activity in visual perception, particularly for objective discrimination, and point to future studies using other stimulation methods or model organisms.
bioRxiv (Cold Spring Harbor Laboratory)
December 22, 2025
Carla Pallavicini, Lorena Llobenes, Federico Cavanna et al.
Combining psilocybin with a compassion-focused imagery exercise produces long-term synergistic effects on cognitive absorption, self-compassion, and decentering. In a sample of 105 participants, those who received a compassion imagery prime before taking psilocybin showed distinct changes in brain network interactions—particularly among attentional, executive, and default mode networks—compared to those who simply focused on breathing. fMRI-based classifiers could distinguish the two priming conditions only at a high dose of psilocybin. The findings suggest that pairing psilocybin with compassion-based practices may amplify lasting psychological shifts and reorganize large-scale brain networks, though confirmatory studies are needed.
bioRxiv
January 29, 2024
Juan Ignacio Piccinini, Yonatan Sanz Perl, Carla Pallavicini et al.
preprint
The brain state induced by psychedelic drugs is often studied as a static snapshot, but this work focuses on the transition itself. Using a time-dependent whole-brain model and fMRI data from 15 volunteers given intravenous DMT, the authors show that the drug briefly pushes the brain near a critical point where it becomes maximally responsive to perturbations. This heightened reactivity is concentrated in fronto-parietal regions and visual cortices and correlates with serotonin 5HT2a receptor density. The findings suggest that even a short psychedelic episode can have a lasting influence because minimal perturbations during this transient achieve maximal effect, with the temporal evolution aligning with the drug's pharmacokinetics.
bioRxiv Preprint Server
September 28, 2022
Yonatan Sanz Perl, Carla Pallavicini, Juan Piccinini et al.
preprint
Brain states are often described on a single scale from full consciousness to unconsciousness, but this ignores the complex, high-dimensional nature of brain activity. By combining whole-brain modeling, data augmentation, and deep learning, researchers mapped states of consciousness into a low-dimensional space where distances reflect similarities between states. They found an orderly trajectory from wakefulness to brain-injured patients, with coordinates related to functional modularity and structure-function coupling, both increasing as consciousness is lost. Model perturbations provided a geometric interpretation of state stability and reversibility. The work suggests conscious awareness depends on functional patterns encoded as a low-dimensional trajectory within the vast space of brain configurations.
Psychopharmacology
September 1, 2022
Camila Sanz, Federico Cavanna, Stephanie Müller et al.
Natural speech can reveal whether someone has taken a microdose of psilocybin. In a double-blind, placebo-controlled experiment, 34 healthy adults provided speech samples after consuming either 0.5 grams of psilocybin mushrooms or a placebo. Machine learning classifiers distinguished between the two conditions with high accuracy (AUC ~0.8), based on features such as verbosity and sentiment scores, though semantic variability did not differ significantly. This suggests that low doses of serotonergic psychedelics leave detectable signatures in unconstrained speech, offering a potential low-cost, non-invasive method for monitoring microdosing regimens.
bioRxiv Preprint Server
July 2, 2020
Yonatan Sanz Perl, Carla Pallavicini, Ignacio Pérez Ipiña et al.
preprint
The level of consciousness—how conscious someone is—is often measured by how similar their brain activity is to normal wakefulness. However, this approach misses important information about how stable that state is. Using computer models of the whole brain, the authors show that the stability of a conscious state—how easily it can be disrupted—provides additional, complementary information. They propose a new framework that sorts brain states by both their similarity to wakefulness and their stability, which helps distinguish between different types of unconsciousness: natural sleep, anesthesia, and brain injury. This framework offers a more complete way to characterize and differentiate states of consciousness.