Sleep/wake

Technical term for properties of electrical or neural circuits (flip-flop switch) to rest in two distinct states while avoiding intermediate states (e.g., behavioral state sleep-wake transitions). 

The synchronised oscillatory activity between the intrinsically linked thalamus and cortex. Under normal circumstances there is a level of activity which changes during the sleep-wake cycle increasing during periods of slow wave sleep. Excess synchrony occurs in conditions such as epilepsy. Thiazolidinedione... 

Webster, HH and Jones, BE (1988) Neurotoxic lesions of the dorsalateral pontomesencephalic tegmentum-cholinergic cell area in the rat. II Effects upon sleep-waking states. Brain Res. 458 285-302. 

From time to time it has been suggested that histamine has some role in a number of behaviours and motor activity while the established and marked sedative effect of Hi receptor antagonists, mentioned at the start of this section, has consistently been considered to indicate a role for histamine in arousal and the sleep-waking cycle (see Chapter 22). 

These rhythms seem to be innately programmed although they can be adjusted. For instance, in a normal environment, the sleep-waking cycle of humans is obviously synchronised ( entrained ) with the (24-h) dark-light cycle whereas it assumes a period of around 25-27 h in a (time-free) environment where there are no diurnal cues. Interestingly, when humans are in a time-free environment, the change in the rhythm of... 

Figure 22.1 Pathways projecting to and from the suprachiasmatic nucleus (SCN). Inputs from photoreceptors in the retina help to reset the circadian clock in response to changes in the light cycle. Other inputs derive from the lateral geniculate complex and the serotonergic, Raphe nuclei and help to reset the SCN in response to non-photic stimuli. Neurons in the SCN project to the hypothalamus, which has a key role in the regulation of the reproductive cycle, mood and the sleep-waking cycle. These neurons also project to the pineal gland which shows rhythmic changes in the rate of synthesis and release of the hormone, melatonin...

Probably the most important breakthrough in sleep research came in the mid-1930s when it was discovered that the profile of the electroencephalogram (EEG) changed markedly during the sleep-waking cycle (Fig. 22.4). To this day, the EEG is a major... 

Based on the above aeeount of the neuronal pathways thought to be responsible for the basie sleep-wake cyele, the neurotransmitters that are most likely to be involved in the eyele are those which ... 

Table 22.1 Effects of activation of 5-HT receptors on sleep-waking cycle...

Since most excitatory transmission is mediated by glutamate this must be involved in the sleep-waking cycle. It certainly mediates the input of the retinohypothalamic tract to the SCN, apart from afferent inputs more generally to the ARAS, etc. So far, specific in vivo manipulation of the direct glutamate input to the SCN has not been possible. 

Cape EG and Jones, BE (1998) Differential modulation of high-frequency gamma-electroencephalogram activity and sleep-wake state by noradrenaline and serotonin microinjections into the region of cholinergic basalis neurons. J. Neurosci. 18 2653-2666. 

Garcia-Garcia, F and Drucker-Colin, R (1999) Endogenous and exogenous factors on sleep-wake cycle regulation. Prog. Neurobiol. 58 297-314. 

Portas, CM, Bjorvatn, B and Ursin, R (2000) Serotonin and the sleep-wake cycle special emphasis on microdialysis studies. Prog. Neurobiol. 60 13-35. 

Team members provided and coordinated referrals to a variety of community agencies, and supported caretakers in learning about normal infant development, sleep-wake patterns, and feeding schedules and appropriate foods. Caretakers were also helped to understand the infants developmental strengths, what would effectively soothe him/her, and what play activities were appropriate at certain ages. 

Promote appropriate patient sleep-wake cycles... 

If patient is sleep deprived, consider altering the patient s environment and possibly a nighttime sedative to promote an appropriate sleep-wake cycle... 

Studies of sleep-active neuronal discharge across the sleep-wake cycle in freely moving animals provide important information about the hypnogenic process (see below) but, because of sampling limitations, are not suitable for systematic mapping of the exact locations of putative hypnogenic neurons. The application of the c-Fos immunoreactivity (IR) method to map sleep-active neurons has stimulated several advances. C-Fos IR is a marker of neuronal activation in most brain sites immunohistochemically labeled neurons can be mapped systematically. The localization of c-Fos IR following sustained sleep, but not... 

Alam, Md. N., Gong, H., Alam, T., Jaganath, R., McGinty, D., Szymusiak, R. (2002). Sleep-waking discharge patterns of neurons recorded in the rat perifornical lateral hypothalamic area. J. Physiol. 538, 619-31. 

Hayaishi, 0. (2002). Molecular genetic studies on sleep-wake regulation, with special emphasis of the prostaglandin D2 system. J. Appl. Physiol. 92, 863-8. 

McGinty, D. Szymusiak, R. (2000). The sleep-wake switch a neuronal alarm clock. 

Nitz, D. Siegel, J. M. (1996). GABA release in posterior hypothalamus across sleep-wake cycle. Am. J. Physiol. 271, R1707-12. 

Sleep-waking discharge of neurons in the posterior lateral hypothalamus of the albino rat. Brain Res. 840, 138-47. 

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