Theme 9 SLEEP AND WAKE (v. Sleep disorders. (Insomnia:, Sleep related…
Theme 9 SLEEP AND WAKE
i.Neuronal regulation of the sleep-wake cycle: The circadian timing system and sleep homeostat.
The classic phase markers for circadian rhythm timing are:
Core body temperature minimum.
Cortisol plasma levels.
The wake-sleep cycle at glance
The Brain Tires
As energycarrierATP breaksdown, adenosinbuildsup and triggersneuronactivity
The hypothalamic suprachiasmatic nucleus (SCN)
The Brain Sleeps
Melatonin triggers the onset of sleep
SCN activates VLPO neurons at night which releases GABA and galanin in the Hypotalamus.
The Brain Awakes
Neurotransmittersof theascendingreticular activatingsystem(ARAS) likeDA, His, 5-HT, and NE
iii.Wakefulness and the ascending reticular activating system (ARAS).
Consciousness is an arousal and awareness of environment and self.
b) The prefrontal cortex
In turn exerts top-down regulatory control over ascending modulatory systems, favoring the processing of incoming information and filtering of irrelevant stimuli.
iv.Levels of consciousness: Basal forebrain cholinergic system and attention.
The MS andvertical limb of the DB project to hippocampus and entorhinal cortices.(B)
brain stem cholinergic system
pedunculopontine tegmental nucleus (PPT)
latero dorsal pontine tegmentum (LDT)
Basal forebrain cholinergic system
Major cholinergic pathways (A)
The magnocellular basal forebrain cholinergic system
diagonal band of Broca(DB
nucleus basal is magnocellular is(nBM).
medial septal nucleus (MS)
ii. Sleep organization and regulation: the REM sleep .
Sleep is a vital, complex state with as yet unknown functions.
It consist into two sleep states, rapid eye movement (REM) and non-rapid eye movement (NREMorSWS).
Sleep is highly organized and regulated.
REM and non-REM sleep alternate within one sleep cycle, which lasts 90-120 minutes in adult humans.
Body temperature drops
Heart rate slows
Non-rapid eye movement (NREM) sleep
STAGE 3 AND 4
5-15 minutes each
Slow-wave /Delta Sleep
Stage 4 slightly deeper.
Body repair itself
Non-Rapid eye movement (NREM) sleep
Non-Rapid Eye Movement (NREM) sleep
Sense of falling common
Very light sleep
10 minutes in first cycle
Brain activity similar to waking levels
Rapid eye movement (REM) sleep cycle restarts after REM
v. Sleep disorders.
Sleep related breathing disorders
Circadiam Rhythm Sleep-Wake disorders
Sleep movement disorders