Sleep physiology, Hypothalamus, Thalamus, Limbic system

Question 1

What structure in the hypothalamus regulates the sleep cycle via circadian rhythm

Answer 1

Suprachiasmatic nucleus (SCN)

Question 2

What hormones does the circadian rhythm control the nocturnal release of?

Answer 2

• ACTH
• Prolactin
• Melatonin
• NE

Question 3

The pineal gland releases melatonin, how is this initiated - what structure initiates it?

Answer 3

SCN releases NE
- NE influences the pineal gland to release melatonin

Question 4

What is SCN regulated by?

Answer 4

Environment (light)

Question 5

What drugs will decrease N3 sleep and REM sleep?

Answer 5

• Alcohol
• Barbiturates
• Benzodiazepines

Question 6

What EEG waves dominate the N1 stage of sleep?

Answer 6

Theta

Question 7

What waves have the highest frequency and lowest amplitude?

Answer 7

Beta (awake, eyes open)

Question 8

What waves have the lowest frequency and highest amplitude?

Answer 8

Delta (stage N3)

Question 9

During what stage of sleep does bruxism occur?

Answer 9

Stage N2

Question 10

How are benzos useful for night terrors and sleepwalking?

Answer 10

Occur during stage N3 of sleep cycle and benzodiazepines reduce N3 and REM sleep

Question 11

What are the 4 stages of sleep?

Answer 11

• Stage N1 (theta)
• Stage N2 (sleep spindles and K complexes)
• Stage N3 (delta)
• REM sleep (Beta waves)

Question 12

During what stage of sleep do sleep spindles and K complexes form on EEG?

Answer 12

Stage N2

Question 13

What percetage of sleep does each stage take up?

Answer 13

• Stage N1 (5%)
• Stage N2 (45%)
• Stage N3 (25%)
• REM sleep (25%)

Question 14

How often does REM sleep occur?

Answer 14

Every 90 minutes, duration of REM increases through the night

Question 15

The activity of what causes eye movements during REM sleep?

Answer 15

PPRF (Paramedian pontine reticular formation / conjugate gaze centre)

Question 16

What wave forms will be seen on EEG during REM sleep?

Answer 16

Beta waves

Question 17

Sleepwalking, night terrrors and bedwetting occur during what stage of sleep?

Answer 17

Stage N3

Question 18

What stage of sleep has sexual arousal and possibly serves as a memory processing function?

Answer 18

REM sleep

Question 19

Describe the physiological changes which occur during the REM stage of sleep?

Answer 19

• Loss of motor tone
• Increased brain O2 use
• Variable HR/BP
• Increased ACh

Question 20

What changes occur in sleep in the elderly?

Answer 20

• Decreased REM
• Decreased N3
• Increased sleep latency
• Increased early awakenings

Question 21

What changes occur in sleep in depression?

Answer 21

• Increased REM
• Decreased REM latency
• Decreased N3
• Repeated nightime awakenings
• Early morning awakening (terminal insomnia)

Question 22

What stage of sleep is effected in narcolepsy?

Answer 22

Decreased REM latency

Question 23

What part of the hypothalamus controls hunger?

Answer 23

Lateral nucleus

Question 24

What is the lateral nucleus stimulated by and inhibited by?

Answer 24

• Stimulated by ghrelin
• Inhibited by leptin

Question 25

What does the Anterior nucleus (hypothalamus) control?

Answer 25

Cooling (Air Con), paraympathetic

Question 26

What does the posterior nucleus control (hypothalamus)?

Answer 26

Heating, sympathetic

Question 27

What do the supraoptic and paraventricular nuclei synthesise?

Answer 27

ADH and oxytocin

Question 28

What does the Preoptic nucleus release?

Answer 28

GnRH

Question 29

What does the Preoptic nucleus control?

Answer 29

- Thermoregulation - Sexual behaviour

Question 30

What condition is a result of a failure of GnRH-producing neurons to migrate from olfactory pit?

Answer 30

Kallman's syndrome

Question 31

What is the main function of the thalamus?

Answer 31

Major relay for all ascending sensory information except olfaction

Question 32

What inputs does the Ventral postero-lateral nucleus (thalamus) receive?

Answer 32

- Spinothalamic - DCML

Question 33

Where do the inputs from the Ventral postero-lateral nucleus (thalamus) go to?

Answer 33

Primary somatosensory cortex (parietal lobe)

Question 34

What inputs go to the Ventral postero-medial nucleus (in thalamus)?

Answer 34

- Trigeminal (face sensation) - Gustatory pathway (taste) Very Pretty Makeup goes on the face

Question 35

Where do inputs go to from the Ventral postero-medial nucleus (thalamus) go to?

Answer 35

Primary somatosensory cortex

Question 36

What inputs does the Lateral geniculate nucleus (thalamus) receive?

Answer 36

Vision - CN II - Optic chiasm - Optic tract Lateral = Light

Question 37

Where do inputs from the Lateral geniculate nucleus (thalamus) go to?

Answer 37

Primary visual cortex

Question 38

Where does the Medial geniculate nucleus (thalamus) receive inputs from?

Answer 38

Superior olive and inferior colliculus of tectum (hearing) Medial = Music

Question 39

Where do inputs from the Medial geniculate nucleus (thalamus) go to?

Answer 39

Primary auditory complex (temporal lobe)

Question 40

Where does the Ventral anterior and lateral nuclei (thalamus) receive inputs from?

Answer 40

- Basal ganglia - Cerebellum (motor) Venus astronauts love to move

Question 41

Where do inputs from the Ventral anterior and lateral nuclei (thalamus) go to?

Answer 41

Motor cortices (frontal lobe)

Question 42

What is the function of the limbic system?

Answer 42

- Emotion - Olfaction - Behaviour modulation - ANS function Feeding, Feeling, Fighting, Feeling, Fucking (sex) (5Fs)

Question 43

What structures does the limbic system consist of?

Answer 43

- Hippocampus (memory) - Amygdalae (processing emotions associated w. fear) - Mammilary bodies (recollective memory) - Anterior thalamic nuclei (episodic memory) - Cingulate gyrus (processing emotions, behaviour regulation, regulate motor function) - Entorhinal cortex (memory formation, navigation, perception of time)

Question 44

What can damage or decreased activity to the mesocortical pathway result in?

Answer 44

Negative symptoms, anergia, apathy, lack of spontaneity (connects to frontal lobe)

Question 45

What does the mesocortical pathway connect?

Answer 45

Ventral Tegmental Area (VTA) (dopamine producing) to the frontal cortex

Question 45

What does the Mesolimbic pathway connect

Answer 45

VTA (dopamine producing) to Nucleus accumbens (ventral striatum, part of BG), Prefrontal cortex and Amygdala

Question 46

An increase in activity of the Mesolimbic system is associated with what condition?

Answer 46

Schizophrenia (delusions, hallucinations)

Question 47

A decrease in activity of the nigrostriatal pathway will result in what symptoms?

Answer 47

Extrapyramidal symptoms (dystonia, akathisia, parkinsonism, tardive dyskinesia)

Question 48

What dopamenergic pathway is targeted by antipsychotics?

Answer 48

Mesolimbic (can affect nigrostriatal leading to tardive dyskinesia OR Tuberoinfundibular -> hyperprolactinemia)

Question 49

What dopamenergic pathway is affected by movement disorders?

Answer 49

Nigrostriatal pathway

Question 50

The tuberoinfundibular pathway connects what?

Answer 50

Hypothalamus to anterior pituitary

Question 51

A decrease in activity of the tuberoinfundibular pathway can result in what side effect?

Answer 51

- Galactorrhea (hyperprolactinemia), decr libido, gynaecomastia

Question 52

What are the 2 primary dopamine producing areas of the brain?

Answer 52

- Ventral Tegmental Area (VTA) - Substantia Nigra (2 of them) Located in midbrain