Wakefulness brain regions

A link between 5-HT release and increased waking is supported by evidence from in vivo microdialysis of cats and rats. This has confirmed that the extracellular concentration of 5-HT in all brain regions studied to date is lower during both SWS and REM sleep than in the awake state (see Portas, Bjorvatn and Ursin 2000). Interestingly, if behaviour is maintained at a constant level, the activity of 5-HT neurons does not show circadian variation although 5-HT turnover in the brain areas to which they project... 

Bjorvatn, B and Ursin, R (1998) Changes in sleep and wakefulness following 5-HTlA ligands given systemically and locally in different brain regions. Rev. Neurosci. 9 265-273. 

Overview of brain regions controlling wakefulness and REM sleep... 

Orexin neurons innervate all the major brain regions implicated in the generation of wakefulness including the aminergic and cholinergic brainstem... 

Engber, T.M., Dennis, S.A., Jones, B.E., Miller, MS, Contreras, PC. Brain regional substrates for the actions of the novel wake-promoting agent modafinil in the rat comparison with amphetamine. Neuroscience 1998 87(4) 905-911. 

Enhancement of dopamine and norepinephrine actions in certain brain regions may improve attention, concentration, executive function and wakefulness (e.g. dorsolateral prefrontal cortex)... 

Administration of L-tryptophan to humans has been reported to reduce sleep latency and waking time.42-44 Similar results in reduction of sleep latency also have been observed in rats.45 Since tryptophan is a precursor of serotonin, which has been implicated in the mediation of sleep,46 it was assumed that tryptophan produces these effects by increasing the availability of serotonin at sites where serotonin naturally occurs in the brain. However, in addition to its action on brain serotonin, it was suggested that tryptophan may produce its hypnotic effects via a nonserotonergic mechanism.42 The reduction in concentration of both dopamine and norepinephrine induced in various brain regions by the administration of L-tryptophan also correlates with reduction in sleep latency.47... 

M. Thomas et al. Neural basis of alertness and cognitive performance impairments during sleepiness. I. Effects of 24 h of sleep deprivation on waking human regional brain activity. J Sleep Res, 2000. 

Braun, A. R., Balkin, T. J., Wesensten, N. J. et al. (1997). Regional cerebral blood flow throughout the sleep-wake cycle an H2 150 PET study. Brain 120, 1173-97. 

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