PLoS One
January 1, 2026
Matilda Gibbons, Ethan G McBride, Raghuram Holenarasipura Venkatasubbaiah et al.
An adversarial collaboration will test competing predictions from Global Neuronal Workspace Theory and Integrated Information Theory about the neural correlates of consciousness. Non-human primates and mice will perform a go-nogo task with supra-threshold visual and auditory stimuli while neural activity is recorded from multiple cortical areas using Neuropixels electrodes. To causally test timing and location predictions, prefrontal cortex activity will be manipulated via electrical stimulation in primates or optogenetic silencing in mice. The protocol details experimental design, analyses, divergent predictions, and anticipated outcomes.
British Journal of Anaesthesia
February 1, 2024
Cameron P Casey, Sean Tanabe, Zahra Z Farahbakhsh et al.
Many EEG-based measures previously thought to indicate unconsciousness actually track sensory connectedness—awareness of the environment—rather than consciousness itself. Analyzing data from the UNderstanding Consciousness Connectedness and Intra-Operative Unresponsiveness Study, researchers tested 10 resting-state EEG markers derived from unresponsive subjects during dexmedetomidine and propofol sedation and natural sleep. While several markers correlated with reported subjective experience (consciousness), none were specific to consciousness alone; each was also linked to connectedness. Loss of normalized-symbolic transfer entropy (front to back) was associated with connectedness across all conditions, and the shift from disconnected consciousness to unconsciousness involved significant decreases in permutation entropy and spectral exponent. The findings caution against equating unresponsiveness with unconsciousness.
Cell Reports
August 29, 2023
Eli J Müller, Brandon R Munn, Michelle J. Redinbaugh et al.
A whole-brain computational model of the corticothalamic system, built from empirical data on targeted and diffusely projecting thalamocortical nuclei, reproduces key features of propofol anesthesia: reduced network integration, lower state diversity, impaired susceptibility to perturbation, and decreased corticocortical coherence. These signatures indicate suppressed information transfer across the cerebral cortex. Selectively stimulating the matrix thalamus in the model restores signatures of conscious arousal, matching empirical results in macaques, and produces wake-like information processing states. The findings suggest that matrix thalamocortical projections modulate large-scale cortical attractor dynamics to enable the complex communication states that support conscious awareness.
PLoS Computational Biology
July 1, 2022
Michelle J. Redinbaugh, Mohsen Afrasiabi, Jessica M. Phillips et al.
Deep brain stimulation (DBS) of the central lateral thalamus in macaques can produce episodes of vacant staring with low-frequency brain oscillations, termed vacant, perturbed consciousness (VPC). The likelihood of VPC depended on stimulation frequency. During VPC, measures of neural complexity and integration decreased, and communication in cortico-striato-thalamic circuits changed substantially, with increased low-frequency power and coherence, especially in thalamo-parietal and cortico-striatal pathways. These features resembled absence epilepsy. The same DBS method, at different frequencies, can also increase consciousness in anesthetized macaques, offering a flexible tool to study consciousness with fewer confounds and to inform clinical research on consciousness disorders.
bioRxiv Preprint Server
July 27, 2021
Michelle J. Redinbaugh, Mohsen Afrasiabi, Jessica M. Phillips et al.
preprint
Deep brain stimulation (DBS) of the central lateral thalamus in macaques can produce episodes resembling absence epilepsy, termed absence-like activity (ALA), characterized by decreased behavior, vacant staring, and low-frequency oscillations. The likelihood of ALA depended on stimulation frequency. During ALA, neural complexity (entropy) and integration (Φ*), an index of consciousness, decreased, and communication within cortico-striato-thalamic circuits changed substantially. Power spectral density and coherence at low frequencies increased, especially in thalamo-parietal and cortico-striatal pathways. Decreased consciousness and neural integration corresponded to shifts in network configurations that dissociated parietal and subcortical structures. The same DBS method, at different frequencies, can also increase consciousness in anesthetized macaques, offering a flexible tool for studying consciousness and informing clinical research on absence epilepsy and other disorders of consciousness.
bioRxiv Preprint Server
April 7, 2020
Mohsen Afrasiabi, Michelle J. Redinbaugh, Jessica M. Phillips et al.
preprint
Simultaneous recordings from frontal, parietal, striatal, and thalamic regions in macaques during wakefulness, sleep, and anesthesia, along with deep-brain thalamic stimulation, show that parietal cortex, striatum, and thalamus contribute more to the level of consciousness than frontal cortex. This supports Integrated Information Theory over Global Neuronal Workspace Theory and Higher-order Theories, but Integrated Information Theory does not account for subcortical structures like the striatum. The authors propose that thalamo-striatal circuits have a cause-effect structure that generates integrated information.
bioRxiv Preprint Server
October 1, 2019
Michelle J. Redinbaugh, Jessica M. Phillips, Niranjan A. Kambi et al.
preprint
Consciousness requires the capacity to experience the environment and internal states. Recordings from macaques show that during unconsciousness, spiking activity is selectively reduced in deep cortical layers and thalamus, along with diminished interactions at alpha and gamma frequencies. Gamma-frequency stimulation of the central lateral thalamus in anesthetized macaques counteracted these changes and restored consciousness. The findings suggest that the neural correlates of consciousness involve coordinated activity across corticocortical feedforward and feedback pathways, intracolumnar loops, and thalamocortical circuits.