Biology subjects

Sparby, T.

Publications and source records attributed to Sparby, T..

4 recordsLinked to original sources

bioRxiv2026

EEG brain reconfiguration during meditation-induced extended cessation of consciousness: A dense-sampling multi-participant microstate study

Extended cessation (EC) is a rare, non-ordinary meditative endpoint characterized by a temporary absence of reportable phenomenal experience, followed by an extraordinary perceptual vividness, openness, equanimity and affective balance. EC thus offers a unique, non-pharmacological window into the brain dynamics underlying suspension of conscious experience and the subsequent psychological transformations. The present study investigated whole-brain electrophysiological changes induced by EC using a dense-sampling electroencephalographic microstate analysis, in five highly trained meditators. Temporal parameters and transition probabilities of canonical microstates during EC were compared with two control conditions (counting and memory tasks) across six frequency bands (broadband, delta, theta, alpha, beta, gamma). EC was characterized by alterations in global explained variance and coverage of microstates B and C, both associated with self-referential processing. Specifically, EC involved less frequent and shorter occurrences of microstate B, and more frequent and longer occurrences of microstate C. Transition probabilities also reconfigured: transitions from A and B to C increased, whereas transitions from A to B decreased. These broadband effects were distributed across delta, theta, and beta frequency sub-bands. Additional band-specific changes emerged for microstate A and D. Delta band showed longer microstate A and increased B-to-A transitions during EC, while beta band showed less frequent and shorter D and decreased bidirectional B-to-D transitions. These scalp-level findings support a precision re-weighting account of EC, reflecting self-referential reconfigurations with enhanced sensory-anchored inflow. This study provides initial evidence for the neurophysiological correlates of EC, with potential implications for human wellbeing. SIGNIFICANCE STATEMENTExtended cessation is a rare meditative state involving a voluntarily, temporary suspension of conscious experience, offering an exceptional opportunity to study how the brain supports and disrupts conscious awareness without pharmacological intervention. By applying EEG microstate analysis, this study identifies distinct large-scale neural reconfigurations during EC, particularly within microstates linked to self-referential processing. These findings suggest that EC involves a dynamic redistribution of precision and sensory-anchored processing, providing initial neurophysiological evidence for how advanced meditation may reshape conscious experience. This work advances the scientific understanding of non-ordinary states of consciousness and highlights their potential relevance for human well-being.

neuroscience↗

bioRxiv2025

Whole-Brain Models of Minimal Phenomenal Experience: Approaching Criticality through Jhana Meditation

Advanced meditation offers a powerful lens for investigating consciousness and for understanding how sustained training may contribute to human flourishing. In the spirit of neurophenomenology, we combine first-person reports with model-free empirical analyses and formal whole-brain modeling to investigate the mechanisms underlying advanced meditative states and minimal phenomenal experience (MPE). Specifically, we focus on jh[a]na meditation, a type of advanced concentrative absorption meditation (ACAM-J). Advanced practitioners accessed the eight ACAM-J states during ultra-high-field 7T functional magnetic resonance imaging. For each state, we first characterize empirical functional connectivity and then build a mechanistic whole-brain model that reproduces brain activity by modeling the dynamical regimes of different brain networks. We found that the later ACAM-J states, taken here as candidates for MPE, show increased large-scale functional integration and a shift of functional network dynamics toward near-critical working points. The default mode network (DMN) exhibits the largest shift, from a distant noise-driven regime during the control condition to near-critical dynamics during ACAM-J. We also observed that the trajectory of ACAM-J states is non-linear, with prominent reconfigurations at key meditative milestones. Our results suggest that MPE, as instantiated in later ACAM-J states, corresponds to a globally susceptible state where near-critical dynamics dominate. We interpret this near-critical regime as a form of "openness", in which constrained and differentiated patterns of brain activity give way to greater flexibility. In particular, increased DMN susceptibility is correlated with broader attention and reduced narrative thought, consistent with a more flexible mode of self-related processing. In this context, advanced meditation provides a powerful model for studying how sustained contemplative practice can profoundly shape brain dynamics and provide a window into core aspects of consciousness.

neuroscience↗

bioRxiv2025

Neuroelectrophysiological correlates of extended cessation of consciousness in advanced meditators: A multimodal EEG and MEG study

In some contemplative traditions, "extended cessation" (EC) refers to a state of advanced meditation in which the meditator intentionally suppresses their own consciousness and re-emerges with a profound sense of clarity and equanimity. Here, we present the first electrophysiological study of EC, in which five meditators underwent concurrent electroencephalography (EEG) and magnetoencephalography (MEG) recording. EC significantly reduced alpha power. EC also tended to increase neural complexity, unlike other states in which consciousness is absent (e.g., sleep, anesthesia, disorders of consciousness). Our results indicate that the neural correlates of EC are distinct from other states that induce loss of consciousness and that complexity is not a sufficient condition for consciousness, while also providing new insights into the implications of advanced meditation for human flourishing.

neuroscience↗

bioRxiv2025

Endogenous suspension and reset of consciousness: 7T fMRI brain mapping of the extended cessation meditative endpoint

Extended cessation (EC), an advanced meditative state in which consciousness is volitionally suspended and later reset with immense mental clarity, equanimity, and peace, offers an endogenous model for investigating the mechanisms of consciousness. Using ultra-high-resolution 7T fMRI with dense within-subject sampling (N=3), we quantified whole-brain activity, functional and effective connectivity, cortical gradients, and eigenmodes, and related them to chemoarchitecture and cognitive maps. EC is marked by increased activity in unimodal regions, down-regulation in transmodal regions, subcortex, and brainstem, an expansion of the principal gradient, and decrease in low-order global eigenmodes. Cognitive decoding linked EC to heightened perceptual clarity and attention, least with mental suffering, and co-varied with histaminergic H receptors topology. These findings challenge predictions of Global Neuronal Workspace and Integrated Information Theory, while supporting the Active Inference Framework. More broadly, EC demonstrates that consciousness can cease without global suppression, suggesting a potential "reset" mechanism that fosters equanimity and the potential for flourishing.

neuroscience↗