BMS11004 - WEEK 6 WEDNESDAY Flashcards
overview sleep
complex behavioural programme associated with drastic changes in behavioural and brain activities, and change in gene expression
define sleep behaviourally
reduced motor activity and stimulus response, stereotypic posture, relatively easy reversibility
name 3 physiological measures for sleep
electromyography
electro oculography
EEG
what does EEG record
measuring synchronous electrical activity from large neuron groups, created by cellular ionic movements, creating electrical field
give advantages of EEG
non-invasive, data easy, high temporal res-measure activity change in milliseconds
give disadvantages of EEG
low spatial res, electric field follow inverse square law so only cortical activity detectable (further away electrode is from activities source means smaller signal)
what Hz is alpha wave?
8-13Hz
what Hz is beta wave?
13-30Hz
how much of sleep is in REM/or not
75% non rem, 25% rem
name first 4 sleep stages - non REM
drowsiness (few min)
light sleep (5-15min)
deep sleep
very deep sleep
sleep stage 1 - explain drowsiness
easily reversible, slow eyes, muscle activity, muscle contracting (falling sensations)
low-voltage activity EEG (mostly theta waves)
sleep stage 2 - explain light sleep
eye movement stop, brain wave slow (occasional burst of rapid brain waves)
body temp, HR drop
EEG sinusoidal waves “sleep spindles” (12-14Hz), biphasic waves “K complexes” (occur episodically alongside low voltage activity)
sleep stage 3 - explain deep sleep
high amplitude, very slow delta waves (0.5-2Hz), interspersed with smaller fast wave
sleepwalking, night terror, talk, wetting bed
parasomnia (during transition between non/REM)
sleep stage 4 - explain very deep sleep
brain produce mostly delta waves
disorientation for several min after wake
slow wave activity increases
sleep stage 5 - explain REM
mimic awake EEG (low voltage, mixed frequency)
rapid eye movements, relating to intense dreams
paradoxical sleep (neuron firing similar to when awake)
brain temp, metabolic rates increase
atonic skeletal muscle (flaccid, paralysis)
eye, middle ear ossicles, diaphragm muscles active to hear impending danger
explain a normal sleeping pattern
stages 1-4 non-REM, stage 5-REM
70-80min returns to stage 2/3 then enter first REM (8-10min)
firstnon REM-end of REM = 90-110min
4/5x per night
explain sleep patterns in young adults
5% in stage 1
most amount stage 2(50-60%)
stage 3/4 (15-20%)
REM 20-25%
how is sleep regulated
diffuse modulatory neurotransmision system
NE/5-HT neurons in brain stem
thalamus control rhythmic behaviour
inhibit motor neuron to prevent muscle contraction
what does lesioning brain stem cause
sleep/coma
activation of brain stem neuron has downstream impacts for neuron, precede awakening, stimulating brain stem cause awakening
give an overview of non-REM stage sleep brain characteristic
slow-wave
less firing in brain stem
reduce muscle tension, low movement, temp, energy consumpts
give summary of REM stage sleep characteristics
similar to awake firing states, no frontal lobe activities
inhibit motor neuron
low voltage fast EEG, muscle paralysis, movement commanded by brain not carry out
dreamings
give theories of dreaming
strange imagery- brain isn’t fully functional
circuit testing
exercise synapses when no external activity to ensure work
memory consolidation = learning
define circadian rhythm
endogenous and persist without environmental cues, modulated by external cues (zeitgeber) adopting rhythm to environment. can usually require sensory stimulation but works without as well
what is main circadian clock
suprachiasmatic nucleus, lesioning causes decreased CR, regulates sleep timings
what provides input to SCN for timing sleeps
intrinsically photosensitive ganglion cells in eyes
what is a K complex (stage 2)
delta wave, maintain sleep and memory consolidation
what are sleep spindles (stage 2)
brief powerful burst of neuron fires at superior temporal gyri, cc, thalamus
role in memory consolidation
what is deepest sleep wave type?
delta
what is awake wave type?
beta
