Functional connectivity of the circadian clock and neural substrates of sleep-wake disturbance in delirium

A possible mechanism of disrupted circadian rhythms in delirium was identified using resting-state functional connectivity. Thirty-four delirious patients and 38 non-delirious controls were scanned for resting-state functional MRI. Seed-based connectivity of the suprachiasmatic nucleus was compared between the groups. In delirious patients functional connectivity from the circadian clock was increased to the dorsal anterior cingulate cortex and decreased to the posterior cingulate cortex, parahippocampal gyrus, cerebellum, and thalamus. A dysregulation of the default mode network and mental coordination processing areas by the circadian clock may be the underlying pathophysiology of sleep-wake cycle disturbance and symptom fluctuation in delirium.