aleep and consciousness

Question 1

Function of general sleep

Answer 1

1) RESTORATIVE HYPOTHESIS (REGENERATION)

2) ADAPTIVE REACTION

Question 2

REGENERATION)

Answer 2

in animal expts: may cause death, loss of weight and body care
after deprivation: SWS4 and REM is made up
effect of physical effort? sleep pattern of patients confined to bed

Question 3

ADAPTIVE REACTION

Answer 3

avoidance of predators

REM – effect of meaningful stimuli – chance to survive

Question 4

FUNCTIONS OF REM

Answer 4

developmental hypothesis: newborns of predators (and man) need more
in learning and memory: selective REM deprivation slows down learning, memory functions are impaired

Question 5

4 phases and REM

Answer 5

o Frequency gets lower, amplitude increases
o Just before sleep still alpha waves, phase 2 sleep spindles, 3 and 4 deep relaxation (slow wave)
o Tonic REM with phasic activity
o 90 minute cycles throughout the night, about 7 hours of sleep, 3-4 REM phases → differs

Question 6

Neuronal Regulation of Sleep in Wakeefulness → producing area between two levels of transaction (EEG)

Answer 6

o Cerveau isolé → permanent sleep (all raphe are cut from brain)
o Encephale isolé → unchanged sleep pattern (at least some raphe are still at brain)

Question 7

• ARAS

Answer 7

(Ascending reticular activating system and Raphe system

Question 8

Neuronal Regulation of Sleep in Activation of specific neural circuits triggers sleep and wakefulness

Answer 8

o Cholinergic neurons of ARAS → awaken
o Slow electrical stimulation of thalamus → fall asleep
o Posterior hypothalamus → arousal (ergotrop)
o Anterior hypothalamus → sleep (trophotrop)

Question 9

• REM → ACh neurons become active in pons

Answer 9

o Loss of muscle tone
 Inhibitory neuron in medulla → to motor neuron and muscle
o Eye movements, PGO waves → Pons → lateral geniculate → occipital cortex
 Each wave is synchronized with an eye movement
o Desynchronized EEG
o Hippocampal theta rythm

Question 10

• Biochemical regulation of SWS

Answer 10

o Glycogen metabolism → adenosine is released (inhibitory neuromodelator) → induces SWS
 Caffeine is adenosine inhibitor
o Following sleep deprivation
 S-factor (muramil peptides)
 DSIP (deep sleep inducing factor)
o Sleep proting substance (SPS, uridin)
o Stimulation of basal forebrain cholinergic system causes ACh increase in cortex and concomitant EEG desynchronization

Question 11

• Biochemical regulation of REM

Answer 11

o Noradrenergic system → locus coeruleus (medulla)
o Serotinergic system → raphe nuclei
o Both stop during REM, increasing activity of cholinergic system (pons) during REM

Question 12

• Sleep and thermoregulation

Answer 12

o Part of basal forebrain is center (preoptic part of hypothalamus) of thermoregulation → its warming causes SWS
 Warming face or body increases SWS
 During SWS brain temperature decreases
 During REM temperature of brain increases

Question 13

Sleep disorders

Answer 13

• Insomnia
• Narcolepsy
  Sleep attack
  Cataplexy
  Sleep paralysis
  Hypnagogic hallucinations
• Somnambulism

Question 14

• Narcolepsy

Answer 14

→ disorder of REM

Question 15

• sleep attack

Answer 15

normal sleep for a few minutes

Question 16

• cataplexy

Answer 16

loss of muscle tone durink awake state

Question 17

• Sleep paralysis

Answer 17

before going to sleep or before waking up.

Question 18

• Hypnagogic hallucinations

Answer 18

frightning

Question 19

• Somnambulism

Answer 19

combined sleep and wakefulness

Question 20

Circadian rhythms

Answer 20

Biological clock

Question 21

• Retinohypothalamic pathway

Answer 21

o Nucleus suprachiasmaticus (in hypothalamus) → pineal glad (melatonin).
- SCN transplanted into other brain causes change of circadian rhythm → the secretion of the hypothalamic hormones is also changed

Question 22

ATTENTION passive and active

Answer 22

orientating reaction (reflexes)
vs selective attention

Question 23

• Skinner-Yingling model

Answer 23

o	Frontal cortex → modality specific inhibition in NR – relevant channel activated
o	MRF (mesencephalic reticular formation)→ result of inhibition of NR

Question 24

Consciousness criteria

Answer 24

correct awareness of self and enviroment and space

continuity and clarity

Question 25

• Disorders of consciousness (organic disorders with known causes)

Answer 25

o Hypnogenic disturbance (somnolentia, spoor, coma); Lesion in ARAS, Disturbed EEG
o Permanent vegetative state (apallic syndrome – cortex) - Cognitive functions are lost, Autonomic functions remain normal, Pathological reflexes, Decorticate muscle tone, Lesion in neocortex
o Akinetic mutism ; Lesion in medial prefrontal lobe or anterior cingular region
o Delirium (hallucinations with normal arousal)
o Confused state (e.g. after epileptic seizure)
o Locked-in syndrome. Conscious but unable to move or to express. Lesion in pons or midbrain

Question 26

 When glutamate is activated channel,

Answer 26

ca and na enter into the neuron → activating pattern

 Strong synapse activated whole neuron

Question 27

o Mechanism of LTP

Answer 27

 In resting state magnesium blocks the channel, when activation by glutamate molecule magnesium is pushed away and calcium is allowed to enter
 Glutamate binds with NMDA receptor
 Depolariszation evicts MG Ion

Question 28

Amnestia retrogerade

Answer 28

before trauma is lost