Sleep is generally subdivided into "stages" on the basis of its electrophysiological characteristics; however, within each sleep stage the functional state of the brain changes continuously. Hélène Bastuji and colleagues (NEUROPAIN CRNL) show in the Journal of Neuroscience that the likelihood that a painful stimulus will lead to arousal depends on the state of functional correlation between sensory areas and high-level, associative cortical areas immediately before the stimulus occurs. Fluctuations in communication between cortical areas preceding the noxious stimulus may thus determine reactivity, facilitating or preventing the transfer of information from sensory networks to multiple higher-level cortical networks.
Bastuji H, Cadic-Melchior A, Magnin M, Garcia-Larrea L. J Neurosci, April 2021, doi: 10.1523/JNEUROSCI.2935-20.2021