Final Flashcards
Sleep, Neuropsychological Assessment, Dementia and Multiple Sclerosis
What is chronobiology?
The study of biological rhythms
What are biological rhythms?
Inherent timing mechanisms that control various biological processes –> Circadian rhythm
What drives behaviour in biological rhythms?
External cues i.e. Sunlight, and internal cues i.e. melatonin
What are the 4 biological rhythms?
Circannual –> yearly, i.e., bird migration
Circadian –> daily, i.e., sleep-wake cycle
Ultradian –> less than a day, i.e., eating cycles
Infradian –> more than a day, i.e., menstrual cycle
What are free running rhythms?
Rhythm that the body devises in absence of all external cues, for example sleeping patterns when deprived of sunlight and darkness.
What are zietgerbers?
A cue from the environment that signals a “reset” in the biological rhythm, i.e., light and dark
What is suggested to be the neural basis of the biological clock?
The suprachiasmatic nucleus, located at the base of the hypothalamus.
What happens if the superchiasmatic nucleus is damaged or disrupted?
Damaged: Issues with timing of daily activities
Disrupted: Issues with length and timing of sleep
Where does the suprachiasmatic nucleus receive its information?
The retinohypothalamic tract –> light signals the release of excitatory neurotransmitters to entrain the rhythmic activity of the SCN
How does the Suprachiasmatic nucleus control our biological rhythms?
By giving input about the appropriate timing of behaviours through the circadian timing system
What is the circadian timing system?
The control of behaviours by slave oscillators that affect another behaviour.
How can we objectively measure sleep?
Recording equipments such as polysomnography through electroencephalogram, electromyogram and electrooculogram.
How do the three measures of polysomnography work?
Electronic equipment records readouts from electrodes attached to the sleeper. (A) EEG made from a point on the skull relative to a neutral point on the ear. (B) EMG made between two muscles, such as those on the chin and throat. (C) EOG made between the eye and a neutral point on the ear.
What are the 5 stages of sleep?
W – Waking
N1 - NREM stage 1
N2 - NREM stage 2
N3 - NREM stage 3
R-sleep – REM
What rhythm is active during the Waking state?
Beta rhythms, but may also produce alpha rhythms when relaxed
What occurs during non-rem sleep 1 (NREM1)?
Sleep onset–> Moves from beta activity to theta-wave activity
What occurs during non-rem sleep 2 (NREM2)?
Asleep –> Theta-waves, sleep spindles and k-complexes
What occurs during non-rem sleep 3 (NREM3)?
Deep sleep–> Difficult to arouse and groggy when woken up, delta rhythms
What occurs during r-sleep (REM sleep)?
Atonia, EEG pattersns are similar to the beta, alpha and theta-wave activity (possibly because they are dreaming)
What is characteristic of a typical night’s sleep?
Progressing through the sleeping stages in order, replacing the W-stage with REM as the cycle reverses.
What is a somnogram?
A sleep graph of an individual’s sleep cycling throuhgh their stages in the night.
What is true about sleep patterns as humans age?
Time asleep tends to decrease, REM sleep makes up less of that sleep too
What are some feats of NREM sleep (all stages)?
Maintain muscle tone – can sleep in various postures/positions
Body temperature and heart rate drop; growth hormone release increases
Can talk in our sleep, grind our teeth, flail our limbs – restless leg syndrome
Sleepwalking occurs
Dreaming can occur, though it is usually less vivid than during REM
Can have lucid dreaming during NREM, where we are aware of the dreams as we dream them.
What are some feats of REM sleep?
Our eyes move.
Our toes, fingers, and mouth will twitch.
Erections in males – regardless of whether accompanying dreams had sexual content in them or not
Mechanisms that regulate body temperature stop.
Body temperature moves toward whatever the room temperature is, so you might wake up extremely cold or extremely hot…
Experience paralysis and atonia.