Second, animals exhibit an increased arousal threshold during sleep, although they can still be aroused by strong stimuli, thus distinguishing sleep from paralysis or coma.
After a disturbed night the sleep depth and arousal threshold tend to increase [11].
In addition to anatomical abnormalities, the maintenance of upper airway patency is dependent upon neuromuscular activation of pharyngeal dilators, ventilatory control, and the arousal threshold.
If unconscious evaluations exceed a critical arousal threshold, distinct emotions (which are conscious, intensive, and directed toward the evaluated contents) may arise.
Multiple measurements of arousal threshold (cm H2O) in response to air-jet stimulation applied alternately to the nares were made in both active sleep and quiet sleep when infants slept both prone and supine.
Abnormalities have been described in sympathicovagal balance, arousal threshold and latency, breathing pattern at rest and apnea frequency, ventilatory response to hyperoxia or hypoxia, heart rate regulation and ability to autoresuscitate during severe hypoxia.
