Sleep & Dreams Flashcards
What is an electroencephalograph (EEG)
machine measuring brain activity displaying it on a screen or print out. Important part of polysomnography. Also, know as EEG.
Nrem-1 waves
first stage. hypnagogic sensations/brief moments when you feel as though your falling
Nrem-2
after 10 mins. Becoming less responsive to the environment, sleeping soundly. If woken, may not realize that you have been sleeping. Sleep spindles occur in the brain.
Nrem-3
after 25 mins, enter stage 3. The EEG begins to show some delta waves, the number gradually increases. Now very unresponsive to environment. Much harder to wake.
Nrem-4
no dramatic change. Sleep gets gradually deeper, delta waves become more common until they dominate the EEG recordings. At this point, loud noise or shaking could wake you. would be grotty and disorientated.
REM sleep
90 mins on, dramatic change occurs. EEG pattern suddenly becomes very mixed in comparison to slowed delta waves from before. Eyes rapidly moving from side to side beneath the eyelids. Rest of the body still temporarily paralysed. If woken much less grotty - and will almost certainly remember dream.
What is polysomnography?
A study of a sleeping individual, recording multiple physical changes in the brain and body. Also measures eye movement and heart rate.
What are sleep spindles?
Sharp spikes of electrical activity occurring in the brain.
What is adenosine?
In addition to the role of melatonin making us sleepy, a chemical called adenosine builds up in our neurons during the day as a natural by-product of the brians activities. Causes us to feel tired and fatigued. When we sleep this build-up is cleared, and the adenosine gets replaced by energy in the form of glycogen
One of the main functions of the SCN?
SCN controls the release of melatonin (a hormone that makes us sleepy) SCN sends a message to the pineal gland, and this gland releases the hormone. Melatonin is released when it gets darker. Usually released into the bloodstream in the evening when the sun goes down.
What are Delta Waves?
Brain waves emerging from the thalamus and are generally associated with slow-wave sleep. (during third stage of sleep, begin to appear) often known as deep sleep
What is the suprachiasmatic nucleus?
Located in the hypothalamus. The SCN gets info from nerve cells in the eyes about whether it is light or dark allowing the brain to know when to sleep
What are circadian rhythms
Known as ‘body clock’ Physical, mental and behavioural changes that followed a 24-hour cycle. Natural processes respond primarily to light and dark and affect most living things
How does melatonin affect us?
Makes a person start to feel tired and eventually drift off. It DOES NOT act instantly usually will start to be released in the early evening. Melatonin levels peak in the middle of the night and fall back down towards day time levels
