![]() It has been suggested the fetus is not awake with wakeness occurring in the newborn due to the stress of being born and the associated activation of the locus coeruleus. Research suggests that orexin and histamine neurons play distinct, but complementary roles in controlling wakefulness with orexin being more involved with wakeful behavior and histamine cognition and activation of cortical EEG. Orexin deficiency has been identified as responsible for narcolepsy. These exist in areas adjacent to histamine neurons and like them project widely to most brain areas and associate with arousal. Another key system is that provided by the orexins (also known as hypocretins) projecting neurons. Histamine neurons in the tuberomamillary nucleus and nearby adjacent posterior hypothalamus project to the entire brain and are the most wake-selective system so far identified in the brain. Several systems originating in this part of the brain control the shift from wakefulness into sleep and sleep into wakefulness. The posterior hypothalamus plays a key role in the maintenance of the cortical activation that underlies wakefulness. Another effect of wakefulness (which may or may not be related to this) is that it lowers the small stores of glycogen held in the astrocytes that can supply energy to the brain's neurons-one of the functions of sleep it has been proposed is to create the opportunity for them to be replenished. The longer the brain has been awake, the greater thing the spontaneous firing rates of cerebral cortex neurons with this increase being reversed by sleep. Hypersomnia - unalert, unvigilant, unwatchful Sleep disorder, sleep disturbance - faculty, mental faculty, module - celerity, dispatch, fastness, promptitude, promptness, quickness, rapidity, rapidness, speed, speediness, suddenness, swiftness Īdvert, attend, be careful, give ear, hang, mind, pay heed - alertness, on the qui vive, sharp-sightedness - vigilance, watchfulness, weather eye - alertness, vigilance, wakefulness, watchfulness - alert, qui vive - alertly, observantly, vigilantly, watchfully - early, immediate, prompt, quick, straightaway Īlert, watchful - aware, cognisant, cognizant, conscious (observation observance watching), (attentiveness attention attending notice), (careful alert attentive obliging), (interest) ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |