Why Do We Sleep? We sleep one third of our lives away!

Neurology of Consciousness Brainstem & cerebellum; arousal & sleep Damage to brainstem; coma (no conscious awareness) Motor cortex is still active during sleep, but brainstem blocks messages causing sleep paralysis

Circadian Rhythm Rhythms our bodies naturally follow Annual (seasonal depression) Monthly (ladies…) 24 hour (body temp rises in morning, dips in afternoon and drops before sleep) 90 minute Hypothalamus triggers the pineal gland to increase melatonin in the evening; makes you tired We sleep less than our ancestors….why? Thanks to Thomas Edison Bright light decreases the production of melatonin

Sleep Theories 1.Protects 2.Recuperates: restores & repairs tissue 3.Helps Remembering: rebuilds our fading memories. 4.Growth: pituitary gland releases growth hormone 5.Hardwires: transfers new memories into long term memory, sleep after studying and you will remember it better.

How to measure sleep Brain sends electrochemical messages (brain waves) Slower waves are associated with greater relaxation

How to measure sleep beta waves active concentration & focus alpha waves Awake but relaxed, daydreaming, meditation DREAMING!

How to measure sleep theta waves Tasks become so automatic (repetitious) that you mentally disengage Very positive mental state, usually get good/creative ideas here Driving home and not remembering delta waves slowest frequency, greatest amplitude Deep dreamless sleep Difficult to wake, may become disoriented Releases growth hormones and fortifies our immune system

Stage One Very brief; transition from wakefulness to sleep Approximately 5 minutes, you’ll never remember Easily awaken from this stage; probably insist that you were never asleep. T heta waves

You are paralyzed while you sleep Sleep paralysis Your body is paralyzed except your eyes, chest & sometimes minor extremities like toes, fingertips and lips natural protection mechanism that prevents you from acting out your dreams Sleep paralysis turns on and off throughout a night Why we Sleep Walk?

Why do I feel like I’m falling? Hallucinations: false sensory experiences; not actually experiencing what you are feeling Hypnagogic jerk: the falling sensation Involuntary twitch, not sure why we do it Maybe…natural transition form alert to sleep, neurons misfiring Maybe…brain misinterprets as a primate falling from a tree Maybe…brain misinterprets sleep as death, jump starts to wake you

Stage Two Theta waves marked by sleep spindles (short bursts of rapid brain waves) Over the course of the night, you will spend ½ of your sleep in this stage

Stage Three/Four Stage 3 is short, transitions you to stage 4 Delta waves (slow waves, considered deep sleep) Gets shorter as you approach morning Increased exercise will increase the amount of time in these stages Night Terrors

Sleep Cycle Once you complete stage 4, you move backwards through the stages until you reach stage 1 Before waking, you experience REM sleep NOTE: Stage 4 eventually disappears while REM gets longer Sleep stages Awake Hours of sleep REM ASAP Science: Hitting the snooze button (2:21)ASAP Science: Hitting the snooze button

Marked by Rapid Eye Movement, Alpha waves Motor cortex is active, but brainstem blocks messages (paralysis) Heart rate increases, breathing is shallow and rapid Essential for remembering, learning and problem solving Improve immune system function Dreams can occur at any stage but most likely in REM sleep When REM starts, snoring stops! REM Sleep

REM Rebound If deprived of REM sleep, at your next opportunity to sleep, you will skip the sleep cycle and go right back to REM Think about it…. REM deprived all week, but get plenty of sleep on the weekends….what will you remember?

Why do we yawn? Not much is known Yawn in response to reduced brain metabolism Stretching your neck muscles increases heart rate, thus increasing alertness Unborn babies can yawn Meaning that you unconsciously do it You are more likely to yawn after a friend or relative than a complete stranger (more empathy)

What else is contagious? LAUGHING! (6:30)

What would happen if you stopped sleeping? (3 mins)