Brain Rhythms and Sleep 1 Flashcards
brain rhythms
what are all brain rhythms characterised by?
think patterns and rates of patterns
by periodic re-occurrence of similar patterns at a relatively constant rate
oscillations in the cerebral cortex
what waves are prominent in stage 1 of N-REM sleep
theta waves
oscillations in the cerebral cortex
what are found in stage 2 of sleep in an EEG and what are they used for
-sleep spindles
- used to transfer info from short term memory to long term memory
oscillations in the cerebral cortex
what waves are prominent in stage 3 and 4 of N-REM sleep
Delta waves
oscillations in the cerebral cortex
what waves are prominent in REM sleep
Low-voltage, high frequency waves (similar to beta waves when awake)
recording oscillations in cerebral cortex
what are features of the electroencephalogram (EEG)
think cortical activity, how it can effect a patient and neurological conditions
- measurement of generalized cortical activity
- non-invasive and painless
- can diagnose neurological conditions like epilepsy and sleep disorders
EEG
what does the EEG record?
think electric fields, synapses and cells in cerebral cortex
records small electric fields generated by synaptic currents in pyramidal cells in cerebral cortex
EEG
why do larger EEGs occur when asleep/ in deep sleep?
think type of firing
there is more synchronous firing of neurons (this usually only happens during sleep)
what drives brain oscillations
what 2 ways can brain oscillations be driven?
- rhythms can be led by a pacemaker (synchronous firing)
- arise from collective behaviour of all participants
what drives brain oscillations
what is a powerful pacemaker that can effect the cortex?
the Thalamus
what drives brain oscillations
outline how the thalamus acts as a pacemaker for the cortex
think thalmocortical axons, excitation and oscillation of cells
- Thalamus use thalmocortical axons to communicate with cortex
- this excites cortical neurons
- cortical cells will oscillate to the same rhythm as thalamus
circadian rhythm
what does circadian rhythm do apart from modulate sleep wake cycle
- schedules thinks like temperature, hormone release, feeding, metabolism, drinking, behaviour
circadian rhythms
what is the circadian rhythm regulated by
the Suprachiasmatic nucleus
Circadian rhythms
outline the Suprachiasmatic nucleus (SCN) pathway
think light, time and effects
- light sensitive input pathway
- Clock (SCN)
- output pathway
circadian rhythm and the sleep wake cycle
define sleep
readily reversible state of reduced responsiveness and interaction with the environment
hypnograms of adult sleep
what type of sleep increases in duration during sleep
REM sleep
Stages of sleep
outline stage 1 of N-REM sleep
think types of waves involved,how regular and type of eye movement and length of time it lasts
transitional sleep full of alpha rhythms/waves that become less regular as you eyes start to make slow, rolling movement.
only lasts a few mins
stages of sleep
outline stage 2 of N-REM sleep
think frequency of sleep spindles in Hz, type of waves and their amplitude and what generates them, effects on eye movement and time it lasts
deeper than stage one, and includes occasional 8-14 Hz sleep spindles and high-amplitude K-complex waves generated by a thalamic pacemaker. eye movements almost cease
lasts 5-15 mins
stages of sleep
outline stage 3 of N-REM
think type of waves and eye/body movement
large amplitude, slow delta rhythms/waves. eye and body movement absent.
stages of sleep
outline stage 4 of N-REM
think type of EEG rhythm observed, the waves’ frequency in Hz and how long it lasts
deepest stage of sleep. Large EEg delta rhythms of 2Hz or less
lasts between 30-40 mins
stages of sleep
Outline REM sleep
think eye movement, type of EEG rhythms and when REM occurs
frequent eye movements, fast EEG rhythms/waves.
sleep will lighten from stage 4 to 2 for about 15 mins before entering brief period of REM
stages of sleep
what happens to NREM and REM during the night progresses
general reduction in NREM and sleep and increase in REM
physiological changes during N-REM and REM sleep
what are 2 physiological changes during N-REM sleep
think HR, BP, RR and muscles
- steady HR, BP and Repsiration rate
- Muscles relaxed
physiological changes during N-REM and REM sleep
what are 2 physiological changes in REM sleep
think HR, BP and RR and muscles
- Fluctuating HR, BP and respiration rate
- skeletal muscles PROFOUNDLY relaxed
Sleep and memory
outline how sleep aids memory before learning
think hippocampus, file-transfer and memory consolidation
- hippocampus has limited stoage capacity
- sleep takes info from hippocampus to nearby cortices (file-transfer mechanisms)
- this frees up short term memory and makes prior memories more permenant (memory consolidation)
sleep and memory
what time of sleep is rich in NREM?
early night sleeps
sleep and memory
what is NREM useful for
think factual information, forgetting things, information recovery
- useful for consolidating Factual, textbook like information
- useful for forgetting information we no longer need
- useful for recovering information you couldnt retrieve before sleep
sleep and memory
what is the main benefit of REM sleep
- helps brain gather disparate sets of knowledge fostering creativity and better problem solving
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