sleep

Question 1

how is sleep measured

Answer 1

through all 3 of EEG, EOG (ocular ie eye movements) and EMG (muscles around jaw)

Question 2

stages of sleep + relevance to dreaming DIAGRAM

Answer 2

stage 1 and 2 is non rem, stage 3 and 4 also non rem, but stage 5 rem in 1 and 2, EOG low, IN 3 and 4, EOG getting more, until in REM, it’s a lot (much slower) (eyes are flickering) EEG in stage 5 similar to that when awake= further evidence that dreaming occurs in REM

Question 3

DIAGRAM sleep cycles and HR/breathing

Answer 3

Sleep occurs in cycle, with the peaks of EEG at REM- at these points, there are also peaks in HR and breathing

Question 4

what controls sleep- different parts of brain

Answer 4

RAS (reticular activating system) controls CONCIOUSNESS- goes up from brainstem to hypothalamus and cortex: orexin/hypocreti (NT’s) stimulates it lateral hypothalamus causes wakefulness, venterolateral preoptic nucleus (anterior hypothalamus) causes sleep, both by affecting the RAS

suprachiasmatic nucleus synchronises sleep with lower light leves- causes pineal gland to release melatonin

Question 5

effects of sleep deprivation

Answer 5

psychiatric- irritability, depression, stress neurological- less attention, risk of errors, neurodegeneration: different parts of brain activated in sleep deprived person somatic (systemic)- IR, less leptin, immunity, risk of cancer

Question 6

how does body compensate for sleep loss

Answer 6

body makes you faster to get to sleep next time, NREM sleep (slow sleep) increases, as well as increased REM sleep

Question 7

functions of sleep

Answer 7

recovery, energy conservation, avoiding predators, and memory consolidation (you remember more when sleeping)

Question 8

dreams

Answer 8

occurs mostly in REM sleep, but can occur in NREM- mostly emotional rather than real life, shown by fact that during dreams, limbic system activity much higher than in frontal lobe- needed perhaps for consolidating memory

Question 9

causes of insomnia

Answer 9

physiolocial- apnoea or chronic pain brain dysfunction- depression, NIGHT SHIFTS

Question 10

treatment of insomnia

Answer 10

sleep hygiene- eg avoiding caffein at high, or heavy meal, comfortable environment etc hypnotics (drugs enhance GABA) or sleep cognitive behavioural therapy (CBT)

Question 11

hypersomnia+ survey

Answer 11

sleepiness during daytime, often due to OBA Epworth sleepiness scale related to sleepiness in the daytime

Question 12

narcolepsy

Answer 12

falling asleep during daytime but disturbed sleep in night- lack of control of REM sleep due to orexin/hypocretin deficiency- leads to cataplexy (sudden loss of muscle tone)

Question 13

sleep and neurological diseases

Answer 13

sleep may be a cause of neurological diseases, but it may be a consequence, often an early marker/symptom