APPP 06: Gross Anatomy of the CNS – Consciousness and Sleep Flashcards
What are the 2 types of waking (awake/conscious)?
- active waking (aW)
- quiet waking (qW)
What are the 2 types of sleep?
- slow wave sleep (SWS) / non-REM sleep (NREM)
- paradoxical sleep / rapid eye movement (REM) sleep
While waking and sleep, in general, are readily distinguishable, they are each split into subtypes that are best quantified by what?
muscle and brain activity, described as waves
What do electromyograms (EMG) and electroencephalograms (EEG) do?
help discern the current state of a person
What do EMGs measure?
muscle tension
What do EEGs measure?
brain activity
- electrodes placed on scalp record electrical activity of the brain (mostly from the cortex)
How do EMGs and EEGs both measure activity?
using amplitude and frequency measurements
What does an increase in amplitude mean in EMGs and EGGs?
more voltage
What does an increase in frequency mean in EMGs and EGGs?
spikes happen more often
- hertz (Hz) = cycles per second
What is sleep?
behaviourally quiescent state
What is slow-wave sleep characterized by?
- decreased motor tone – still some tone, entering sleep
- loss of awareness to surroundings
- staged from light sleep to deep sleep by the pattern of rhythmic slow waves, indicating marked synchronization of neuronal firing
What is REM sleep characterized by?
- motor atonia – tone in antigravity muscles disappears during this stage of sleep
- dreaming
What are the stages of sleep?
4 stages of slow-wave sleep followed by an REM sleep stage
- states of active inhibition of different arousal circuits in the brain
What are the 4 stages of slow-wave sleep?
stage 1: light sleep
- eye movement slow
- loss of awareness
- easily awakened
stage 2: light sleep
- heart rate slows
- occasional high amplitude slow waves (delta)
stage 3: deep sleep
- breathing slows, muscles relax
- more delta waves
stage 4: very deep sleep
- very deep, dreamless sleep
- mostly delta waves
(sleepwalking occurs in slow wave sleep)
What is paradoxical sleep typified by?
rapid eye movement (REM)
- phasic periods include REM
- tonic periods do not
What is paradoxical sleep more accurately defined by?
- behavioural sleep (quiescence)
- complete muscle atonia, and paradoxically, cortical activity typical of waking
What does motor atonia during REM do?
prevents movement during dreaming
What is idiopathic rapid eye movement sleep behaviour disorder?
- nocturnal dream enactment behaviour that occurs in REM and occurs every night – punching, kicking, falling out of bed, talking, screaming
- some medications may promote this (antidepressants, beta blockers)
What is the cause of idiopathic rapid eye movement sleep behaviour disorder?
loss of motor atonia – dysfunction in the lower brainstem nuclei that control REM sleep
What happens to patients with idiopathic rapid eye movement sleep behaviour disorder?
- overtime, they develop motor and cognitive dysfunction
- associated with development of Parkinsons and Dementia and some forms of Narcolepsy
What are the treatment options for idiopathic rapid eye movement sleep behaviour disorder?
- melatonin
- benzodiazepine – enhances activity of GABA
What is the average sleep structure?
- 16 hours awake, 8 hours of sleep
- sleep progresses from slow wave sleep (4 stages) into REM – each forms a sleep cycle
- each REM episode becomes longer towards the end of the sleep period
Describe the sleep structure of infants.
- 16 hours sleeping
- most time in REM
- can transition rapidly from wake into REM
Describe how sleep changes with age.
- slow-wave sleep is maximal in young children and declines with age
- as we age, we spend less time sleeping, in particular slow wave sleep is progressively decreased
- arousal from sleep is difficult in a young child in slow wave sleep or REM, but considerably easier in an elderly individual