Differential engagement of thalamic nuclei orchestrates consciousness states across anesthesia, sleep, and disorders of consciousness.

Consciousness alterations occur across various states, encompassing changes in both arousal and awareness. The contributions of thalamic nuclei of consciousness remain incompletely understood. We analyzed fMRI data across general anesthesia (propofol N = 12, sevoflurane N = 12), disorders of consciousness (DoC) (minimally conscious state N = 9, unresponsive wakefulness syndrome N = 9), and sleep stages (wakefulness N = 31, NREM1 N = 24, NREM2 N = 19), investigating thalamocortical connectivity, local fluctuation (complexity/variability), and their coupling. In our results, propofol affected pulvinar-cortical connections; sleep transitions involved ventral lateral posterior (VLp), medial geniculate, and centromedian nuclei; DoC showed extensive disconnections. Five key nuclei demonstrated state- specific alterations: two first-order (VLp, ventral posterolateral) and three higher-order nuclei (pulvinar, centromedian, mediodorsal), with higher-order nuclei showing more consistent involvement. Decreased complexity/variability occurred in 4-6 nuclei during anesthesia and 4-5 in DoC patients. Nucleus-specific coupling between local fluctuation and connectivity systematically varied with consciousness state. This framework advances understanding of thalamic consciousness orchestration and provides potential therapeutic targets.