Communications biology
March 11, 2025
Juan Ignacio Piccinini, Yonatan Sanz Perl, Carla Pallavicini et al.
6 citations
The transition into a psychedelic brain state is often overlooked in favor of static descriptions of acute effects. Using a time-dependent whole-brain model and fMRI data from 15 volunteers given intravenous DMT, the work shows that a transient of heightened reactivity in fronto-parietal regions and visual cortices correlates with serotonin 5HT2a receptor density. Simulated perturbations suggest that minimal disturbances can achieve maximal effects during this brief period, and the temporal evolution of these features aligns with pharmacokinetics. These findings indicate a mechanism for how short psychedelic episodes may exert a lasting influence over time.
PLoS computational biology
June 6, 2025
Wiep Stikvoort, Eider Pérez-Ordoyo, Iván Mindlin et al.
3 citations
A person's level of consciousness can be assessed by how the brain reacts to stimulation, but this study shows that the brain's unperturbed activity already contains that information. Using personalized whole-brain models fitted to resting-state fMRI data from people in altered states of consciousness (deep sleep, disorders of consciousness), the researchers measured the brain's out-of-equilibrium dynamics—specifically, the asymmetry of effective connections and time irreversibility. They found that states with lower arousal or awareness had less asymmetric connectivity, less irreversibility, and lower complexity in simulated responses compared to controls. The asymmetry in connections drives the nonequilibrium state and, in turn, the differences in complexity.
bioRxiv (Cold Spring Harbor Laboratory)
January 2, 2025
Marcel Socoró Garrigosa, Yonatan Sanz Perl, Morten L. Kringelbach et al.
preprint
Using whole-brain models guided by the Thermodynamics of Mind framework, the authors estimated the brain hierarchy of specific brain states and simulated transitions between states. Applying this to major depressive disorder, they built models of depressed patients before and after psilocybin and escitalopram treatments. Dynamic sensitivity analysis showed that susceptibility to change was on average reduced by escitalopram and increased by psilocybin, and both treatments promoted healthier transitions. These results align with the post-treatment plasticity window opened by serotonergic psychedelics and with the similar clinical efficacy of both drugs observed in clinical trials.
bioRxiv Preprint Server
September 2, 2021
Laura De la Fuente, Federico Zamberlan, Hernán Bocaccio et al.
preprint
The laws of physics are time-symmetric, but dissipative systems like the brain show a preferred temporal direction. Using a deep learning framework inspired by stochastic thermodynamics, researchers analyzed electrocorticography signals from non-human primates. Brain activity during conscious wakefulness could be distinguished from its time-reversed version with high accuracy, using both frequency and phase information. This ability was reduced during deep sleep and ketamine-induced anesthesia. Transitions between slow (≈20 Hz) and fast frequencies (> 40 Hz) mainly contributed to the temporal asymmetry seen during wakefulness. The findings suggest that a preferred temporal direction in neural activity correlates with conscious awareness, linking brain processes to the subjective experience of time's passage.