Local orchestration of distributed functional patterns supporting loss and restoration of consciousness in the primate brain

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: March 11, 2024

Abstract A central challenge of neuroscience is to elucidate how brain function supports consciousness. Here, we combine the specificity focal deep stimulation with fMRI coverage entire cortex, in awake and anaesthetised non-human primates. During propofol, sevoflurane, or ketamine anaesthesia, subsequent restoration responsiveness by electrical thalamus, investigate loss consciousness impacts distributed patterns structure-function organisation across scales. We report that activity under anaesthesia increasingly constrained structure scales, coinciding anaesthetic-induced collapse multiple dimensions hierarchical cortical organisation. These signatures are observed different anaesthetics, they reversed recovery behavioural markers arousal. No such effects were upon stimulating ventral lateral demonstrating specificity. Overall, identify consistent orchestrated specific thalamic nuclei.

Language: Английский

---

Volitional mental absorption in meditation: Toward a scientific understanding of advanced concentrative absorption meditation and the case of jhana

Heliyon, Journal Year: 2024, Volume and Issue: 10(10), P. e31223 - e31223

Published: May 1, 2024

Meditation has been integral to human culture for millennia, deeply rooted in various spiritual and contemplative traditions. While the field of science made significant steps toward understanding effects meditation on health well-being, there little study advanced meditative states, including those achieved through intense concentration absorption. We refer these types states as concentrative absorption (ACAM), characterized by with object leading heightened attention, clarity, energy, effortlessness, bliss. This review focuses a type ACAM known jhana (ACAM-J) due its well-documented history, systematic practice approach, recurring phenomenological themes, growing popularity among scientists more generally media society. ACAM-J encompasses eight layers deep concentration, awareness, internal experiences. Here, we describe phenomenology present evidence from neuroscientific studies that highlight their potential applications practices, psychological sciences, therapeutics. additionally propose theoretical frameworks grounded current cognitive ancient aim stimulate further research broadly, encompassing development endpoints. Studying ACAM, specific practices such ACAM-J, can potentially revolutionize our consciousness mental health.

Language: Английский

---

Neurophenomenological Investigation of Mindfulness Meditation “Cessation” Experiences Using EEG Network Analysis in an Intensively Sampled Adept Meditator

Brain Topography, Journal Year: 2024, Volume and Issue: 37(5), P. 849 - 858

Published: May 4, 2024

Abstract Mindfulness meditation is a contemplative practice that informed by Buddhism. It has been proven effective for improving mental and physical health in clinical non-clinical contexts. To date, mainstream dialogue scientific research on mindfulness focused primarily short-term training applications of reducing stress. Understanding advanced important implications general wellbeing. According to Theravada Buddhist meditation, “cessation” event dramatic experience profound clarity equanimity involves complete discontinuation experience, evidence mastery meditation. Thirty-seven cessation events were captured single intensively sampled meditator (over 6,000 h retreat training) while recording electroencephalography (EEG) 29 sessions between November 12, 2019 March 11, 2020. Functional connectivity network integration assessed from 40 s prior cessations after cessations. From 21 there was linear decrease large-scale functional interactions at the whole-brain level alpha band. In following these linearly returned levels. No modulation observed. The underlain frontal left temporal more posterior decreases connectivity, increase wide-spread increases connectivity. These results provide neuroscientific brain activity related provides foundation future studies

Language: Английский

---

From relaxed beliefs under psychedelics (REBUS) to revised beliefs after psychedelics (REBAS)

Scientific Reports, Journal Year: 2025, Volume and Issue: 15(1)

Published: Jan. 29, 2025

The Relaxed Beliefs Under pSychedelics (REBUS) model proposes that serotonergic psychedelics decrease the precision weighting of neurobiologically-encoded beliefs. We conducted a preliminary examination two psychological assumptions REBUS: (a) foster acute relaxation and post-acute revision confidence in mental-health-relevant beliefs; which (b) facilitate positive therapeutic outcomes are associated with entropy EEG signals. Healthy individuals (N = 11) were administered 1 mg 25 psilocybin 4-weeks apart. Confidence ratings for personally held beliefs obtained before, during, post-psilocybin. Acute subjective experiences measured, as was well-being (before post-psilocybin). negative self-beliefs decreased following psilocybin. Entropy effects under correlated decreases self-belief (acutely at 4-weeks). Particularly strong evidence seen relationship between increases well-being. report first empirical mediates psilocybin's outcomes, provide tentative neuronal mechanism, namely, increased entropy. Replication within larger clinical samples is necessary. also introduce new measure examining robustness these findings utility REBUS model.

Language: Английский

---

Effective Connectivity of Functionally Anticorrelated Networks Under Lysergic Acid Diethylamide

Biological Psychiatry, Journal Year: 2022, Volume and Issue: 93(3), P. 224 - 232

Published: Aug. 6, 2022

Classic psychedelic-induced ego dissolution involves a shift in the sense of self and blurring boundary between world. A similar phenomenon is identified psychopathology associated with balance anticorrelated activity default mode network, which directs attention inward, salience recruits dorsal network to direct outward.To test whether changes networks underlie peak effects lysergic acid diethylamide (LSD), we applied dynamic causal modeling infer effective connectivity resting-state functional magnetic resonance imaging scans from study 25 healthy adults who were administered 100 μg LSD or placebo.We found that inhibitory became excitatory, decreased under effect LSD.The may reflect diminution anticorrelation be key neural mechanism dissolution. Our findings suggest subject-object boundaries across different states consciousness depend upon organized networks.

Language: Английский

---

On the Importance of Being Flexible: Dynamic Brain Networks and Their Potential Functional Significances

Frontiers in Systems Neuroscience, Journal Year: 2022, Volume and Issue: 15

Published: Jan. 21, 2022

In this theoretical review, we begin by discussing brains and minds from a dynamical systems perspective, then go on to describe methods for characterizing the flexibility of dynamic networks. We discuss how varying degrees kinds may be adaptive (or maladaptive) in different contexts, specifically focusing measures related either more disjoint or cohesive dynamics. While disjointed useful assessing neural entropy, potentially serve as proxy self-organized criticality fundamental property enabling behavior complex systems. Particular attention is given recent studies which have been used investigate neurological cognitive maturation, well breakdown conscious processing under levels anesthesia. further these findings might contextualized within Free Energy Principle with respect fundamentals brain organization biological functioning generally, potential methodological advances paradigm. Finally, relevance computational psychiatry, propose research program obtaining better understanding ways that networks relate forms psychological flexibility, single most important factor ensuring human flourishing.

Language: Английский

---

Cortical gradients during naturalistic processing are hierarchical and modality-specific

NeuroImage, Journal Year: 2023, Volume and Issue: 271, P. 120023 - 120023

Published: March 13, 2023

Understanding cortical topographic organization and how it supports complex perceptual cognitive processes is a fundamental question in neuroscience. Previous work has characterized functional gradients that demonstrate large-scale principles of organization. How these are modulated by rich ecological stimuli remains unknown. Here, we utilize naturalistic via movie-fMRI to assess macroscale We identify principal movie delineate separate hierarchies anchored sensorimotor, visual, auditory/language areas. At the opposite/heteromodal end perception-to-cognition axes, find more central role for frontoparietal network along with default network. Even across different stimuli, demonstrated good reliability, suggesting reflect brain state common conditions. The relative position areas within showed stronger numerous correlations behavioral scores compared resting gradients. Together, findings provide an ecologically valid representation underlying while active engaged multimodal, dynamic processing.

Language: Английский

---

Different hierarchical reconfigurations in the brain by psilocybin and escitalopram for depression

Nature Mental Health, Journal Year: 2024, Volume and Issue: 2(9), P. 1096 - 1110

Published: Aug. 5, 2024

Abstract Effective interventions for neuropsychiatric disorders may work by rebalancing the brain’s functional hierarchical organization. Here we directly investigated effects of two different serotonergic pharmacological on brain hierarchy in major depressive disorder a two-arm double-blind phase II randomized controlled trial comparing psilocybin therapy (22 patients) with escitalopram (20 patients). Patients received either 2 × 25 mg oral psilocybin, three weeks apart, plus six daily placebo (‘psilocybin arm’) or 1 (10–20 mg; ‘escitalopram arm’). Resting-state magnetic resonance imaging scans were acquired at baseline and after second dose ( NCT03429075 ). The mechanisms captured generative effective connectivity, estimated from whole-brain modeling resting state each session patient. Hierarchy was determined these sessions using measures directedness trophic levels which captures cycle structure, stability percolation. results showed that created significantly reconfigurations dynamics differential, opposite statistical effect responses. Furthermore, use machine learning revealed significant differential reorganization before treatments. Machine also able to predict treatment response an accuracy 0.85 ± 0.04. Overall, demonstrate ways depression. This suggests hypothesis could be closely linked breakdown regions orchestrating top hierarchy.

Language: Английский

---

Prefrontal contributions to the stability and variability of thought and conscious experience

Neuropsychopharmacology, Journal Year: 2021, Volume and Issue: 47(1), P. 329 - 348

Published: Sept. 20, 2021

Abstract The human prefrontal cortex is a structurally and functionally heterogenous brain region, including multiple subregions that have been linked to different large-scale networks. It contributes broad range of mental phenomena, from goal-directed thought executive functions mind-wandering psychedelic experience. Here we review what known about the their affiliations with networks examine how they may differentially contribute diversity phenomena associated function. An important dimension distinguishes across kinds conscious experience stability or variability states time. This central feature two recently introduced theoretical frameworks—the dynamic framework (DFT) relaxed beliefs under psychedelics (REBUS) model—that treat neurocognitive dynamics as understanding distinguishing between phenomena. Here, bring these frameworks together provide synthesis We close by considering future directions for this work.

Language: Английский

---

A role for the serotonin 2A receptor in the expansion and functioning of human transmodal cortex

Brain, Journal Year: 2023, Volume and Issue: 147(1), P. 56 - 80

Published: Sept. 11, 2023

Integrating independent but converging lines of research on brain function and neurodevelopment across scales, this article proposes that serotonin 2A receptor (5-HT2AR) signalling is an evolutionary developmental driver potent modulator the macroscale functional organization human cerebral cortex. A wealth evidence indicates anatomical cortex follows a unimodal-to-transmodal gradient. Situated at apex processing hierarchy-where it plays central role in integrative processes underpinning complex, human-defining cognition-the transmodal has disproportionately expanded development evolution. Notably, adult especially rich 5-HT2AR expression recent suggests that, during early development, neural progenitor cells stimulates their proliferation-a critical process for evolutionarily-relevant cortical expansion. Drawing multimodal neuroimaging cross-species investigations, we argue by contributing to expansion being prevalent its hierarchy brain, major both functioning. Owing unique excitatory downstream cellular effects, neuronal agonism promotes neuroplasticity, learning cognitive psychological flexibility context-(hyper)sensitive manner with therapeutic potential. Overall, delineate dual 5-HT2ARs enabling modulation

Language: Английский

---