Wakefulness#Mindfulness

The longer the brain has been awake, the greater the synchronous firing rates of cerebral cortex neurons. After sustained periods of sleep, both the speed and synchronicity of the neurons firing are shown to decrease.{{cite journal | last1=Vyazovskiy | first1=VV | last2=Olcese | first2=U | last3=Lazimy | first3=YM | last4=Faraguna | first4=U | last5=Esser | first5=SK | last6=Williams | first6=JC | last7=Cirelli | first7=C | last8=Tononi | first8=G | title=Cortical firing and sleep homeostasis | journal=Neuron | volume=63 | issue=6 | pages=865–78 | year=2009 |doi=10.1016/j.neuron.2009.08.024 | pmc=2819325 |pmid= 19778514 }}

Another effect of wakefulness is the reduction of glycogen held in the astrocytes, which supply energy to the neurons. Studies have shown that one of sleep's underlying functions is to replenish this glycogen energy source.{{cite journal | doi = 10.1016/0301-0082(94)00057-O | last1 = Benington | first1 = JH | last2 = Heller | first2 = HC | title = Restoration of brain energy metabolism as the function of sleep | journal = Progress in Neurobiology | volume = 45 | issue = 4 | pages = 347–60 | year = 1995 | pmid = 7624482 | s2cid = 39737626 }}

{{Main|Ascending reticular activating system |Arousal}}

Wakefulness is produced by a complex interaction between multiple neurotransmitter systems arising in the brainstem and ascending through the midbrain, hypothalamus, thalamus and basal forebrain.{{cite journal | last1 = Brown | first1 = RE | last2 = Basheer | first2 = R | last3 = McKenna | first3 = JT | last4 = Strecker | first4 = RE | last5 = McCarley | first5 = RW | title = Control of Sleep and Wakefulness | journal = Physiological Reviews | volume = 92 | pages = 1087–1187 | year = 2012 | issue = 3 | pmid = 22811426 | pmc = 3621793 | doi = 10.1152/physrev.00032.2011}} The posterior hypothalamus plays a key role in the maintenance of the cortical activation that underlies wakefulness. Several systems originating in this part of the brain control the shift from wakefulness into sleep and sleep into wakefulness. Histamine neurons in the tuberomammillary nucleus and nearby adjacent posterior hypothalamus project to the entire brain and are the most wake-selective system so far identified in the brain.{{cite journal | last1 = Takahashi | first1 = K | last2 = Lin | first2 = JS | last3 = Sakai | first3 = K | title = Neuronal activity of histaminergic tuberomammillary neurons during wake-sleep states in the mouse | journal = Journal of Neuroscience | volume = 26 | issue = 40 | pages = 10292–8 | year = 2006 | pmid = 17021184 | pmc=6674640| doi = 10.1523/JNEUROSCI.2341-06.2006 | url = http://www.hal.inserm.fr/inserm-00408027/document | doi-access = free }} Another key system is that provided by the orexins (also known as hypocretins) projecting neurons. These exist in areas adjacent to histamine neurons and like them project widely to most brain areas and associate with arousal.{{cite journal | last1 = Sakurai | first1 = T | title = The neural circuit of orexin (hypocretin): maintaining sleep and wakefulness | journal = Nature Reviews. Neuroscience | volume = 8 | issue = 3 | pages = 171–81 | year = 2007 | pmid = 17299454 | doi = 10.1038/nrn2092 | s2cid = 8932862 }} Orexin deficiency has been identified as responsible for narcolepsy.{{cite journal | doi = 10.1016/S0092-8674(00)81973-X | last1 = Chemelli | first1 = RM | last2 = Willie | first2 = JT | last3 = Sinton | first3 = CM | last4 = Elmquist | first4 = JK | last5 = Scammell | first5 = T | last6 = Lee | first6 = C | last7 = Richardson | first7 = JA | last8 = Williams | first8 = SC | last9 = Xiong | first9 = Y | title = Narcolepsy in orexin knockout mice: molecular genetics of sleep regulation | journal = Cell | volume = 98 | issue = 4 | pages = 437–51 | year = 1999 | pmid = 10481909 | doi-access = free }}

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 with cognition and activation of cortical EEG.{{cite journal | last1= Anaclet | first1= C. | last2= Parmentier | first2= R. | last3= Ouk | first3= K. | last4= Guidon | first4= G. | last5= Buda | first5= C. | last6= Sastre | first6= J.-P. | last7= Akaoka | first7= H. | last8= Sergeeva | first8= O. A. | last9= Yanagisawa | first9= M. | title= Orexin/Hypocretin and Histamine: Distinct Roles in the Control of Wakefulness Demonstrated Using Knock-Out Mouse Models | journal= Journal of Neuroscience | volume= 29 | issue= 46 | pages= 14423–14438 | year= 2009 | pmid= 19923277 | pmc= 2802289 |doi=10.1523/JNEUROSCI.2604-09.2009}}

It has been suggested the fetus is not awake, with wakefulness occurring in the newborn due to the stress of being born and the associated activation of the locus coeruleus.{{cite journal | last1 = Lagercrantz | first1 = H | title = The birth of consciousness | journal = Early Human Development | volume = 85 | issue = 10 Suppl | pages = S57–8 | year = 2009 | pmid = 19762170 | doi = 10.1016/j.earlhumdev.2009.08.017 }}

• Dream argument
• Eugeroic
• High-conductance state
• Lucid dream
• Sleepwalking

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Category:Cognition

Category:Mental states