Noradrenergic tuning of arousal is coupled to movement transitions

Matching arousal state to an animal's behavioral demands is crucial for efficiently allocating cognitive and metabolic resources. Prior studies implicate cortical noradrenergic (NA) signaling in behavioral state changes, but whether this reflects a global signal and how it affects arousal remain unclear. Here, we examine the locus coeruleus (LC), the main source of cortical norepinephrine, in movement transitions and clarify its arousal-promoting potential during emergence from anesthesia. Using physiological recordings, fiber photometry, optogenetics, and behavioral tracking, we show that LC^NA activity covaries with anesthetic depth and that LC^NA activation coincides with the return of movement during anesthetic emergence. Likewise, in awake animals, movement transitions are coupled to distinct patterns of LC^NA activity. LC^NA activation can increase sympathetic arousal under anesthesia, but LC^NA modulation does not significantly affect anesthetic emergence. Together, these studies reveal LC^NA to have a more limited causal role in promoting behavioral arousal and a nuanced effect on arousal coupled to movement.