S2 L9 - Sleep and Circadian Rhythms Flashcards
(16 cards)
How much sleep do people need in our lifetime?
175,000 hours in their lifetime
sleep has a biological function
Sleep is the result of an internal timing mechanism
Wha is the Recuperation theory?
sleep is needed to restore homeostasis
wakefulness causes a deviation from homeostasis
What are the Adaptation theories?
Sleep is the result of internal timing mechanism
Sleep evolved to protect us from the dangers of the night
What are circadian rhythms?
24 hour cycle
(eg sleep wake cycle)
Endogenous and persist without environmental cues
What does the hypothalamus control?
Body temperature, hunger, thirst, circadian cycles
What is the function of the SCN?
Found in the medial hypothalamus
A major internal clock
Lesioning of the suprachiasmatic tract dampens down the circadian rhythm of sleep
regulates the timing of sleep
What is the first stage of sleep?
transition between wakefulness and sleep
muscles still active
eyes show slow gentle rolling movements
some theta activity
What is the second and third stage of sleep?
Sleep gets deeper and deeper
EEG lowers in frequency and higher in amplitude
What is the fourth stage of sleep?
Deepest stage of sleep
Reached in less than an hour and continues for up to half an hour
Relatively high amplitude (DELTA) activity
What is REM sleep?
Rapid eye movement
EEG looks that of a person who is awake and active although EMG is generally quiet
What is the reticular formation?
A set of nuclei located throughout the brainstem
includes neurons located in different part of the brain
Pontine reticular formation is a brain region without clearly defined borders in the centre of the pons
What are pons?
Regulate REM sleep and aspects of wakefulness
sets your bodys level of alertness when you wake up
How can baseline cortical state be altered?
BY ELECTRICAL BRF stimulation in rats
What is the purpose of REM?
Processing of explicit memories
-inconsistent findings
antidepressant REM-blocking drugs do not interfere with memory
difficult to remain in NREM sleep - REM blocking drugs cause periods of wakefulness
What is Freuds interpretation of dreams
dreams are triggered by unacceptable repressed wishes
manifest dreams - what we experience
latent dreams - the underlying meaning
no evidence for this
What is Activation - Synthesis?
dreams due to cortex’s attempt to make sense of random brain activity
