Nature Communications
March 11, 2024
Andrea I. Luppi, Lynn Uhrig, Jordy Tasserie et al.
43 citations
Loss of consciousness under anesthesia increasingly constrains brain activity to follow the brain's physical structure, collapsing hierarchical cortical organization across scales. This effect was observed with three different anesthetics—propofol, sevoflurane, and ketamine—and was reversed by electrically stimulating the central thalamus, which also restored behavioral signs of arousal. Stimulating the ventral lateral thalamus did not produce these effects, showing specificity. The findings identify distributed brain signatures of consciousness that are orchestrated by particular thalamic nuclei.
Communications Biology
September 30, 2024
Pablo Castro, Andrea I. Luppi, Enzo Tagliazucchi et al.
21 citations
Brain activity during unconsciousness, whether from general anaesthesia or slow wave sleep, is dominated by a recurrent functional connectivity pattern primarily mediated by structural connectivity and with a reduced capacity to transition to other patterns. Conscious awareness is characterized by richer brain dynamics measured by entropy and a greater repertoire of connectivity states. These findings suggest that the dynamic exploration of functional connectivity states provides robust and generalizable markers for the state of consciousness across different conditions.
bioRxiv (Cold Spring Harbor Laboratory)
May 18, 2023
David Aquilué-Llorens, Jennifer S. Goldman, Alain Destexhe
2 citations
preprint
Whole-brain models that simulate neural activity across scales show that spike-frequency adaptation robustly drives synchronized slow-wave activity, a hallmark of unconscious brain states such as sleep and anesthesia. By exploring the parameter space of the TVB-AdEx model using high-performance computing, the authors find that slow-wave occurrence often coincides with a closer alignment between functional and structural brain connectivity. Hyperpolarization can also generate unconscious-like synchronized Up and Down states, potentially explaining how anesthetics work. The model's parameter space reproduces experimentally observed features of sleep and anesthesia.
Elife
October 13, 2025
Guylaine Hoffner, Pablo Castro, Lynn Uhrig et al.
Transcranial direct current stimulation (tDCS) applied to the prefrontal cortex alters the dynamic organization of functional connectivity in the primate brain, with effects depending on the state of consciousness. In awake macaques, cathodal tDCS disrupted the repertoire of connectivity patterns, increased structure-function correlation, decreased Shannon entropy, and favored transitions toward anatomically based patterns. Under deep sedation, anodal tDCS significantly altered brain pattern distribution and reduced structure-function correlation. The stimulation also modified dynamic connectivity arrangements typically associated with consciousness and unconsciousness. These findings suggest that prefrontal tDCS can modulate brain dynamics differently in conscious and unconscious states, offering insights into mechanisms relevant to disorders of consciousness.
arXiv Preprint Archive
October 7, 2025
Maria V. Sanchez-Vives, Arnau Manasanch, Andrea Pigorini et al.
The cerebral cortex generates diverse patterns of activity that shift across brain states such as sleep, wakefulness, anesthesia, and disorders of consciousness, yet a unified definition of brain states remains elusive. This review focuses on two extremes: synchronous states, which predominantly underlie unconsciousness, and asynchronous states, which predominantly underlie consciousness, though exceptions exist. The authors integrate data across levels from local circuits to whole-brain dynamics, examining properties like cortical complexity, functional connectivity, synchronization, wave propagation, and excitatory-inhibitory balance. They make experimental and clinical data, as well as computational models at micro-, meso-, and macrocortical levels, available to readers.