sleep cycle tell Flashcards
what stage is N1 in sleep
the shortest, last for around 8-10 minute
Stage N2,
either increasing in depth to N3 or moving up into REM or light sleep/waking.
what are physiological features of going into deeper sleep
-muscle tone reduces
- eye movement is low
- heart rate slows
- respiratory rate is held at normal
REM sleep
active brain state similar to waking, yet the body is inactive. REM sleep is metabolically demanding as the brain is active, heart and respiratory rate increase and there is increased eye movement, but atonia (lack of muscle tone) in the body.
EEG
investigating the changes occurring during sleep as all stages of the sleep-wake cycle have characteristic rhythms and patterns of activity that can be identified in the EEG
Brainstem reticular formation
control the normal daily patterns of the sleep wake cycle.
what is the reticular formation(RF) made up of?
mix of cells, nuclei and networks that lie within the brainstem and upper cervical regions of the spinal cord
3 things RF plays a role in?
control of arousal levels, or alertness, and consciousness.
what 2 tracts does the RF involve?
1.Ascending Reticular Activating System (ARAS)
2.Descending Reticulospinal tracts
Ascending Reticular Activating System (ARAS
these pathways are not well understood but are involved in arousal and alertness through activation of the higher cortical circuitry.
Descending Reticulospinal tracts
these pathways are involved the control of movement.
how does ARAS increase activity in the thalamus?
conceptual collection of fibres that increase activity in the thalamus and cortex when activated by the reticular formation.
what do the fibres activate in ARAS?
fibres activate the thalamus, and also the major transmitter pathways enabling activation of a large amount of cortex, which maintains a high level of arousal and attention. As a result ARAS is suggested to be involved in: arousal, motivation, integration, motor and autonomic control, reaching all regions of the brain
function of reticular nucleus
controls the activity in the other nuclei, permitting or stopping information flow through this region
what is the key nucleus involved in control of the arousal in the thalamus ?
reticular nucleus
what is another nucleus involved in the arousal system?
centromedian nucleus
what is the function of centromedian nucleus?
connects the basal ganglia and limbic regions with the reticular formation.
what do activation of the certain nuclei in the brainstem reticular formation and the reticular nuclei of the thalamus allow in arousal?
allows or supresses information flow to the thalamus (and the hypothalamus) and out to the cortex