bioRxiv Preprint Server
February 21, 2023
Naomi R. Driesen, Peter Herman, Margaret A. Rowland et al.
5 citations
preprint
Ketamine, an NMDAR antagonist, increased oxidative metabolism (CMRO2) and cerebral blood flow in the prefrontal cortex and other cortical regions, but did not alter resting-state cortical functional connectivity or brain-wide CBF-CMRO2 coupling. Higher baseline CMRO2 was associated with lower task-related prefrontal activation and greater working memory accuracy impairment under both saline and ketamine conditions. These findings suggest that CMRO2 and resting-state functional connectivity index distinct dimensions of neural activity, and that ketamine's impairment of working memory-related neural activity and performance relates to its induction of cortical metabolic activation.
bioRxiv Preprint Server
July 7, 2022
Neil W Bailey, Harry Geddes, Isabella Zannettino et al.
5 citations
preprint
Experienced meditators exhibit distinct neural activity during performance monitoring and error-processing compared to non-meditators. Using a larger sample and more rigorous analyses than prior work, the study clarifies previously inconsistent findings, showing that long-term mindfulness practice is associated with altered brain responses when detecting and processing errors.
bioRxiv Preprint Server
March 9, 2022
Vaibhav Tripathi, Lakshmi Bhasker, Chhaya Kharya et al.
5 citations
preprint
During Sudarshan Kriya Yoga (SKY), a rhythmic-breathing meditation, brain oscillations slow from alpha to theta to delta as the practice progresses. In 43 subjects, alpha-wave amplitude in the parieto-occipital region decreased during rhythmic breathing and dropped sharply in meditation. Theta amplitude and peak frequency increased in the centro-frontal region during rhythmic breathing but remained sustained and low during meditation. Delta-wave amplitude was unaffected by breathing, but both delta power and peak frequency rose during meditation in the centro-frontal region. A decrease in the 1/f aperiodic signal across the brain during meditation suggests a shift in excitation-inhibition balance. Each phase of SKY has a unique electrophysiological signature.
bioRxiv Preprint Server
June 29, 2021
Colin J. Johnston, Paul J. Fitzgerald, Jena S. Gewarges et al.
5 citations
preprint
Ketamine, an antidepressant, interacts with the HPA axis, but its behavioral effects' dependence on this axis is unknown. In male and female mice subjected to chronic unpredictable stress, ketamine (30 mg/kg) or vehicle was given with or without metyrapone to block corticosterone production. No significant drug effects on behavior were observed. Males had higher fecal corticosterone levels and stress-induced increases than females. Ketamine lowered the corticosterone response to a novel stressor only in males. Corticosterone levels correlated with immobility in a behavioral test across all mice, suggesting shared neural circuitry for endocrine and behavioral responses that may be ketamine-responsive only in males.
bioRxiv Preprint Server
April 10, 2017
Karl Frost
5 citations
preprint
A brief breath-awareness practice that induces calm reduces parochialism (favoring one's own group) and increases altruism (self-sacrifice for anyone, regardless of group). This finding supports the hypothesis that cultivating calm broadens prosocial behavior beyond group boundaries, and contradicts the alternative hypothesis that shared practices increase parochialism. In a behavioral experiment, participants played anonymous Public Goods games with both in-group and out-group members; contributions were analyzed using Bayesian model comparison. The results showed that the calming practice decreased parochialism and increased altruism, with no support for the idea that shared practice promotes parochialism.
bioRxiv Preprint Server
September 6, 2025
Winson F.z. Yang, Akila Kadambi, Kilian Abellaneda-Pérez et al.
4 citations
preprint
An advanced meditative state called extended cessation (EC), where consciousness is voluntarily suspended and later resumes with heightened clarity and equanimity, provides a natural model for studying consciousness. Using ultra-high-resolution 7T fMRI with dense sampling of three individuals, the research mapped whole-brain activity, connectivity, gradients, and eigenmodes during EC, linking them to brain chemistry and cognitive maps. EC increased activity in sensory regions, reduced activity in higher-order association areas, subcortex, and brainstem, expanded the principal cortical gradient, and decreased low-order global eigenmodes.
bioRxiv Preprint Server
January 22, 2025
Emma R. Huels, Nicholas Kolbman, Christopher W. Fields et al.
4 citations
preprint
A serotonergic psychedelic, DOI, can reverse general anesthesia and restore wakefulness in rats, even while anesthetics like propofol or isoflurane continue to be delivered. Behavioral arousal was accompanied by recovery of high gamma functional connectivity and restoration of brain network structure. These effects were blocked by a 5-HT2A antagonist, volinanserin, and a non-psychedelic 5-HT2A agonist, lisuride, failed to produce similar results. This provides the first evidence of psychedelic-mediated reversal of general anesthesia and concurrent restoration of brain dynamics associated with normal wakefulness.
bioRxiv Preprint Server
August 29, 2024
Saketh Malipeddi, Arun Sasidharan, Rahul Venugopal et al.
4 citations
preprint
Advanced meditators from the Isha Yoga tradition show shorter intrinsic neural timescales (INTs) during breath-watching, indicating deidentification with mental contents, and no significant differences in INTs between tasks, indicating non-dual awareness. Shorter INTs correlate with self-reported equanimity. The brain's intrinsic neural timescales may serve as a neural marker of equanimity.
bioRxiv Preprint Server
March 4, 2024
Umed Boltaev, Hyun W. Park, Keaon R. Brown et al.
4 citations
preprint
Classic psychedelics are thought to work by inducing neuroplasticity, often measured as dendritic arbor growth. This study tested whether psychedelics directly activate the TrkB receptor or BDNF/TrkB signaling, and whether they cause morphological growth in primary cortical neurons. Using a multimodal screening platform, the authors found that psychedelics do not directly modulate TrkB or BDNF-TrkB signaling, and that 5-HT2A receptor expression and functional levels are low. Psychedelics did not induce dendritogenesis, unlike BDNF which did. These results challenge previous findings and highlight the need for rigorous methods in studying neuroplasticity.
bioRxiv Preprint Server
March 17, 2023
L. Paul Sands, Angela Jiang, Rachel E. Jones et al.
4 citations
preprint
A hypothesized neurocomputational model, valence-partitioned reinforcement learning (VPRL), maintains separate tracks for appetitive and aversive information, generating independent reward and punishment learning signals. This model predicts changes in human choice behavior, subjective experience, and brain activity in regions including the ventral striatum and ventromedial prefrontal cortex during introspection. The findings suggest that valence-partitioned reinforcement learning provides a neurocomputational basis for investigating mechanisms that may drive conscious experience.
bioRxiv Preprint Server
November 1, 2022
Flora Moujaes, Jie Lisa Ji, Masih Rahmati et al.
4 citations
preprint
Ketamine is a promising therapy for treatment-resistant depression, but why some people respond better than others remains unclear. The molecular mechanisms of ketamine are not yet connected to its effects on brain activity and behavior.
bioRxiv Preprint Server
April 3, 2022
Andrew Adamatzky, Jordi Vallverdu, Antoni Gandia et al.
4 citations
preprint
Fungi produce patterns of electrical activity that resemble neural signals in animals, including low and high frequency oscillations and spike trains. This neural-like electrical activity is considered a manifestation of fungal intelligence. The paper discusses fungal cognitive capabilities and intelligence from an evolutionary perspective, questioning whether fungi are conscious and what fungal consciousness means given their complex behaviors, sensory abilities, learning, memory, and decision-making. Experimental evidence supports the conclusion that fungi exhibit forms of cognition, intelligence, and consciousness.
bioRxiv Preprint Server
February 16, 2021
Christopher W. Thomas, Cristina Blanco-Duque, Benjamin Bréant et al.
4 citations
preprint
A single dose of psilocin, the active compound in psychedelic mushrooms, alters sleep architecture in mice. Psilocin delayed the onset of REM sleep and reduced NREM sleep maintenance for about three hours after injection, without causing long-term changes in sleep quantity. The acute brain response featured enhanced oscillations around 4 Hz. When mice were sleep-deprived, psilocin did not change the overall amount of sleep rebound, but it slowed the recovery of slow wave activity in the medial prefrontal cortex. These findings suggest that psilocin affects both global vigilance and local sleep homeostasis, which may relate to its potential antidepressant effects.
bioRxiv Preprint Server
January 15, 2021
Anna Eiserbeck, Alexander Enge, Milena Rabovsky et al.
4 citations
preprint
Conscious perception during the attentional blink appears to be a graded rather than an all-or-none phenomenon. In an event-related potential study with 32 participants, detection of face targets was assessed using objective accuracy, subjective visibility ratings, and brain responses. Behavioral results showed a graded pattern of visual awareness, and corresponding graded differences were observed in the N1, N2, and P3 brain components across visibility levels. These findings suggest that conscious perception during the attentional blink can occur in a graded fashion.
bioRxiv Preprint Server
August 3, 2020
David. J. Schwartzman, Ales Oblak, Nicolas Rothen et al.
4 citations
preprint
Grapheme-colour synaesthesia (GCS) involves automatic, consistent colour experiences triggered by letters or numbers. Two recent studies showed that extensive associative training can produce behavioural, neurophysiological, and phenomenological markers of synaesthesia in non-synaesthetes, but they did not deeply compare the induced experiences to natural synaesthesia. This study analyzed interview transcripts from participants who underwent such training and from natural synaesthetes. Both groups shared several experiential categories, including stability, location, shape, relative strength, and automaticity of colour experience. However, automaticity differed significantly: natural synaesthetes mostly reported automatic experiences, while induced synaesthesia-like experiences were mostly described as wilful. Additional categories emerged only in natural synaesthetes, highlighting heterogeneity. The results indicate that intensive training can alter conscious perception, producing phenomenology substantially resembling natural synaesthesia.
bioRxiv Preprint Server
September 19, 2025
Kenneth Shinozuka, Winson F.z. Yang, Ruby M. Potash et al.
3 citations
preprint
Advanced meditators can enter a state called extended cessation (EC) in which they intentionally suppress consciousness and later emerge with clarity and equanimity. In the first electrophysiological study of EC, five meditators were recorded with EEG and MEG. EC markedly reduced alpha power and tended to increase neural complexity, unlike sleep, anesthesia, or disorders of consciousness. The findings indicate that the neural correlates of EC are distinct from other unconscious states and that complexity alone is not sufficient for consciousness, offering new insights into advanced meditation and human flourishing.
bioRxiv Preprint Server
December 12, 2023
G. Ruffini, F. Castaldo, J. Vohryzek
3 citations
preprint
The paper extends the Kolmogorov Theory of Consciousness by examining how agents that track natural data develop structural and dynamical properties mirroring the world's symmetries. Using Lie pseudogroups to formalize generative models and a neural network as a proxy for the agent, the authors show that data tracking forces the agent's parameters and dynamics to reflect the symmetry properties of the generative world model, leading to a hierarchical organization consistent with the manifold hypothesis. This bridges algorithmic information theory, symmetry, and dynamics, offering insights into neural correlates of agenthood and structured experience.
bioRxiv Preprint Server
February 22, 2023
Daniel Toker, Eli Müller, Hiroyuki Miyamoto et al.
3 citations
preprint
Consciousness depends on bidirectional communication between the cortex and thalamus. A specific pattern of cross-frequency communication—low-frequency waves (1.5–13 Hz) from one region encoded as high gamma waves (50–100 Hz) in the other—is present during conscious states in humans, mice, and rats. This communication diminishes during propofol-induced anesthesia and generalized spike-and-wave seizures, but is enhanced by the psychedelic 5-MeO-DMT. Numerical simulations and neural recordings show that these changes are mediated by shifts in thalamocortical dynamics toward or away from edge-of-chaos criticality, the phase transition between stability and chaos. The findings offer a mathematically defined framework linking thalamic-cortical communication to consciousness.
bioRxiv Preprint Server
January 6, 2023
Adelaida Castillo, Julien Dubois, Ryan M. Field et al.
3 citations
preprint
Ketamine reduced brain-wide low-frequency fluctuations and decreased prefrontal global brain connectivity in healthy adults, while also increasing pulse rate and electrodermal activity. A combination of neural and physiological metrics may predict subjective mystical experiences and reductions in depressive symptoms. The study used time-domain functional near-infrared spectroscopy to measure acute brain dynamics after intramuscular ketamine (0.75 mg/kg) or placebo in 15 participants within a clinical setting, demonstrating the feasibility of this neuroimaging method for larger clinical studies on psychedelics.
bioRxiv Preprint Server
June 17, 2022
Christian Kerskens, David López Pérez
3 citations
preprint
The work examines a theoretical approach from quantum gravity that proposes unknown systems can create entanglement between two known quantum systems only if the mediator itself is non-classical. It suggests this framework might be applied to the brain, noting a long history of speculation about quantum processes underlying consciousness and cognition.
bioRxiv Preprint Server
March 11, 2021
Enzo Tagliazucchi, Federico Zamberlan, Federico Cavanna et al.
3 citations
preprint
Inhaled DMT, a classic psychedelic, produces brief but profound changes in consciousness that vary with context. Using wireless EEG and source imaging, researchers mapped changes in neural oscillations. Frontal and temporal theta power inversely correlated with feelings of unity and transcendence—hallmarks of mystical-type experiences. A machine learning model confirmed the robustness of these results. The findings align with the idea that pre-drug mindset influences subjective experience. Priming individuals to lower theta power before taking a serotonergic psychedelic might increase the likelihood of mystical-type experiences, potentially enhancing well-being and therapeutic outcomes.
bioRxiv Preprint Server
March 27, 2020
Thomas F. Varley, Olaf Sporns, Aina Puce et al.
3 citations
preprint
The brain may operate near a critical tipping point, a state thought necessary for consciousness and complex cognition. Using invasive ECoG recordings from a macaque transitioning between consciousness and unconsciousness under propofol and ketamine, the study found that propofol dramatically restricted the size and duration of neural avalanches and reduced the complexity of brain dynamics, while ketamine allowed more awake-like dynamics to persist. Despite these differences, all states showed some signs of persistent criticality when tested for exponent relations and universal shape-collapse, suggesting that maintenance of critical brain dynamics may be important for regulating conscious awareness.
bioRxiv Preprint Server
March 11, 2020
M Wu, S Minkowicz, V Dumrongprechachan et al.
3 citations
preprint
Prolonged stress can lead to maladaptive learning, but the antidepressant ketamine can restore escape behavior in a learned helplessness paradigm. Dopamine neuron activity in the ventral tegmental area changes systematically during aversive learning and predicts future sensitivity to ketamine treatment. Ketamine's effects depend on dopamine signaling, as chemogenetic inhibition blocks them and optogenetic activation mimics them. In the medial prefrontal cortex, ketamine recovers dendritic spine formation on pyramidal neurons in a dopamine-dependent manner, reversing stress-induced reductions. These findings reveal circuits linking dopamine dynamics, aversive learning, and plasticity enhancements driven by ketamine.
bioRxiv Preprint Server
April 4, 2018
Tomáš Pluskal, Michael P. Torrens-Spence, Timothy R. Fallon et al.
3 citations
preprint
Kava, a medicinal plant used for over 3,000 years in Polynesia, produces kavalactones—compounds that reduce anxiety and pain through mechanisms distinct from benzodiazepines and opioids. This work identifies the seven enzymes that build kavalactones, showing that two of them evolved from an ancestral enzyme to create the core kavalactone structure. Further enzymes then modify this scaffold to generate diverse kavalactones. The pathway was successfully transplanted into bacteria, yeast, and plants, enabling production of kavalactones and their derivatives. This opens a route to developing new treatments for anxiety disorders, which affect over 260 million people worldwide.
bioRxiv Preprint Server
June 24, 2016
Karl Frost
3 citations
preprint
Altruistic behavior and bonding among cooperators are common in animals, but how such behaviors evolve genetically remains debated. Costly ritualized movements may trigger or maintain altruistic sentiments by engaging pre-existing behavioral instincts. This paper models the genetic coevolution of such rituals and altruism, finding that altruism can become fixed in a population or cycle over time, depending on the balance of costs and benefits. When cycling occurs, altruism persists but population mean fitness declines with the introduction of bonding rituals.