Sleep and Dreams

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* We have solid knowledge on sleep but are still looking for better treatments * How can we sleep in different habitats? Underground, deep sea, and space * Recently discovered: people in a study on space sleeping found that the individuals went lethargic and had depression issues, didn’t move much and avoided crucial exercise (important because we don’t want to send depressed people on long voyages) * Origin of the word sleep: somnus (roman god of sleep) and hypnos (greek god of sleep)= part of the confusion between sleep and hypnosis? But hypnosis has nothing to do with sleep * Hippocrates was the father of medicine, was right about some of the symptoms from sleep deprivation * Aristotle had a cycle of why we sleep

* Von Haller’s idea of sleep was similar to Aristotle, with his focus on the head being responsible for sleep, but instead of cooling, it was blood pressure * They were trying to focus on something more specific

* Piéron: first physiological perspective of sleep, thought that the substance would build up during the day and lead to sleep at night, that substance he called hypnotoxin * Hans Berger: discovered the EEG, very important because it showed that the brain had some sort of activity that could be recorded * Hard to record what is in the brains because of brain matter, bones, tissue etc. Another challenge is to make sense of what we are recording * Neural synchronicity: they have to activate in sync with other neurons, makes them more easily detectable and more powerful * Sleep spindles: kind of brainwaves, burst of lines when recorded, sign that the person is very much asleep * K complex: very high amplitude followed by very low amplitude, but the average amplitude is still higher than what you would usually find, gives us a good indication that the person is asleep * Kleitman: considered father of modern sleep research, thought that sleep was a very passive state * Observe a sleep deprived cats brain vs normal cat

* Neurochemical methods: see how sleep can be affected by drugs * MRI can help us see how the brain is activated while sleeping * The first measure that you need to study sleep is EEG, brain activity * The second is EMG, the electromyography or activation of the muscles (usually under the chin, easy to detect) * The last is EOG, or the movement of the eyes

* With these three basic measures, you will be able to identify quite a lot when it comes to sleep * But other measures can also be used: heart rate, reflexes, twitches, galvanic skin response, respiration, finger movement etc. * Different montages of electropde placements on the brain can be used with EEG to study brain activity (the way you install your electrodes will influence your results) * If both electrodes are placed at the same spot on both sides, there will be matching electric patterns, but if one is placed a little lower than the eye and the other is placed a little higher than the other eye, the patterns will be reversed a more exaggerated * Sleep recording: per 30 seconds of recording, you would have the equivalent of one page recorded on paper * With computers, we can now have paperless studies on sleep * Actigraph: watch type device that will record movement (if you move, it probably means that you are awake etc.) * Rechtschaffen + Kales: came up with a way of dividing the different sleep stages so that they can be studied more easily * Always a debate of whether stage one is sleep or awake and very relaxed (a person would not drop a pen they are holding at stage one, people can still maintain certain functions) * You will start seeing spindles, k complex or both at stage two of sleep, that is when you would drop the object * Awake and REM sleep waves are very similar (we need other measures to be able to differentiate them) * In stage one, the eyes start rolling in their sockets and rolling backwards...
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