Sleep Disorders

Question 1

Sleep and memory

Answer 1

Sleep improves memory and learning (EEG patterns during sleep resemble those during learning)

Hippocampal activity during sleep correlates with subsequent improvement in performance

Consolidation becomes strong during sleep

Question 2

Biological clock

Answer 2

Periodic functions in psychological functioning

Circadian rhythms: 24hrs. Influential in regulation of sleep and other functions (eating, drinking, body temperature, etc)

Circannual: seasons

Question 3

Suprachiasmatic Nucleus (SCN)

Answer 3

Branch of optic nerve (retinohypothalamic path) that connects retina with SCN. Coupling between circadian System and light-dark cycle

Controls the release of melatonin in the pineal gland. Melatonin released mostly at night, starting about 2-3 hrs before bedtime

Question 4

Preoptic area

Answer 4

Thermoregulator - receives info from thermoreceptors in skin

Implicated in non-REM sleep onset

Right temperature is around 2 degrees less than during the day

Question 5

Inhibited areas during sleep

Answer 5

Reticular formation - influence physiological arousal

Locus Coeruleus - active after stressful event

Histamine -excitatory hormone
Orexin- necessary to stay awake

Acetylcholine - releases during wakefulness and REM sleep. Important for attention and learning

Question 6

Stages of sleep

Answer 6

1: release of serotonin, theta waves, 5 mins

2: theta waves and bursts of higher frequency waves (k-complex) then sleep spindles generated in thalamus.
Increase in number after learning, more sleep spindles more memories encoded

3&4: slow wave delta waves become prominent . Reduction on sensory input

5/REM: high frequency alpha, beta, and gamma waves. Most dreams occur here. Like awake during the day but GABA inhibits muscle movements (paralysis) increases activity in limbic area and occipital lobe, inhibition in frontal lobe

Each cycle is approximately 90mins with REM lasting longer in each cycle. About 4 cycles per night

Question 7

Sleep and GABA

Answer 7

More GABA released during sleep

Question 8

Sleep as a local phenomenon

Answer 8

GABA deficiency

1: somnambulism (sleep walking) motor cortex is awake
2: REM behavior disorder- people who move vigorously during REM periods, acting out dreams
3: lucid dreaming: monitoring areas are wake in frontal lobe (aware of dreaming)
4: sleep paralysis - waking up while still cannot move

Night terrors: abrupt awakenings from NREM sleep accompanied by intense autonomic arousal and feelings of panic