8: Sleep Flashcards
What is sleep?
A periodic, natural reversable behavioural state of disengagement to the environment
What kind of sleep do dophins have?
Unihemispheric sleep so the hemispheres take turns - allows them to still swim to the surface for oxygen
How does our awareness when asleep change with age?
Children are less easily woken
What is alpha activity?
Associated with rest and sleep
What is beta activity?
Associated with alertness
What waves are seen in stage 1 of sleep?
Theta waves
What waves are seen in stage 2 of sleep?
Sleep spindles and K-complexes
What are sleep spindles?
Bursts of activity seen in stages 2 and 3 of sleep
What are k-complexes?
Negative potentials seen in stage 2 of sleep
What waves are seen in stage 3 of sleep?
Delta waves
What happenes to the number of spindles as we move from stage 2 into stage 3?
They decrease
What waves are seen in stage 4 of sleep?
Delta
What sleep stages are characterized as ‘slow wave’?
3 and 4
What is REM sleep?
Brain activity varies, we have sleep paralysis and dreaming
Why do we need sleep?
Restoration
Adaptation
Why is sleep important for restoration?
It allows us to restore homeostasis and clear toxic waste products much faster
It’s a short period of rest for all neurons
Why is sleep important for adaptation?
We can’t see well at night so it keeps us out of trouble by keeping us immobile
Accross species, what is related to sleep duration?
Metabolic rate
How do genetics affect how long we sleep for?
We have a chronotype caused by the length of the per3 gene
What gene is associated with duration of sleep?
per3
Who stayed awake for 264 hours?
Randy Gardner
How long did Randy Gardner stay awake for?
264 hours
What happened when Randy Gardner had been awake for 2 days?
Irritable, nauseated, memory issues
What happened when Randy Gardner had been awake for 4 days?
Fatigued and had delusions
What happened when Randy Gardner had been awake for 7 days?
Language issues and tremors
How long did Randy Gardner take to recover after the experiment?
2 nights, slept for 14 hours on the first, 10 on the second and then was back to normal
What areas are affected by sleep deprivation?
Motor function, cognitive performance, working memory, mood, executive atention
What are the main ways sleep are measured?
Patient reported outcomes (Sleep diaries)
Actigraphy (Motor activity)
PSG (Multiple signals)
What does PSG stand for?
PolySomnoGrphy
What does PSG record?
EEG (Brain), EMG (Muscles), EOG (Eye signals)
How long does a typical sleep cycle last?
90 mins
What is slow wave sleep?
Stages 3 and 4
How does cortisol affect sleep?
The more we have, the less we sleep
How is the forebrain important to sleep?
In SWS, as neurons are active, other areas of the brain are inhibited
What is the importance of the reticular formation in sleep?
It wakes us up by sending signals to the basal ganglia
What hormones promote arousal?
Noradrenaline (Locus coeruleus) Serotonin (Raphe nuclei) Acetylcholine (Brain stem and basal forebrain) Hypocretin (Hypothalamus) Histamine (Midbrain)
What hormones promote sleep?
GABA
Adenosine
Dopamine
What is the dual process of sleep?
Sleep-wake homeostasis
Cirdadian rhythm
What are Zeitgebers?
External cues that help us keep track of day and night
What part of the brain is responsible for our biological clock?
Hypothalamus
What is insomnia?
Problems sleeping or staying asleep
What causes insomnia?
Overactive thyroid Mental and physical health Medication Stress Environment
What is parasomnia?
A catergory of sleep disorders involving abnormal movements and behaviours
What are some types of parasomnia?
Sleep walking
Night terrors
Sexomnia
What is REM sleep behaviour disorder?
Lack of paralysis during sleep so muscles are free to move and act out dreams
What is the psychological function theory of why we dream?
To preserve neural pathways by providing the brain with stimulation
What is the synthesis theory of why we dream?
Dreams are the brain trying to make sense of neural activity
What type of sleep is better for consolidating declarative memory?
SWS
What type of sleep is better for consolidating procedural memory?
REM