Integrated information, a proposed signature of consciousness, is maximized in a biophysical network model when the nonspecific thalamus drives thick-tufted layer 5 pyramidal neurons into a regime of time-varying synchronous bursting. In this regime, variable spiking dynamics with broad pairwise correlations support enhanced integrated information. The peak in integrated information coincides with criticality signatures and empirically observed layer 5 pyramidal bursting rates. These findings suggest that the thalamocortical core of the mammalian brain may be evolutionarily configured to optimize effective information processing, offering a potential neuronal mechanism linking microscale theories to macroscale signatures of consciousness.
A microscale biophysical network model of layer-5 pyramidal neurons reproduces coarse-sampled dynamics seen in macroscale electrophysiological recordings from macaques and humans. By inverting the model, the authors identify spike and burst dynamics that distinguish unconscious, dreaming, and awake arousal states and reveal their functional signatures. Neuromodulatory arousal shifts neuronal dynamics around a low-dimensional energy landscape, altering the model's response to external stimuli. The work demonstrates how multiscale modeling can connect theories of consciousness across spatiotemporal scales.
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.