AP Psychology - 1.14

How does sleep alter our consciousness?

by reducing alertness, awareness, and perception of events around us

sleep

 a periodic, natural reduction of consciousness

What is much of how people, animals, and even plants function governed by?

circadian rhythms (Latin for 'around the day') (aka "biological clocks")

What is the circadian rhythm of humans?

a cycle of changes (such as temperature or wakefulness) which occur about every 24 hours

What did sleep researchers discover by brain wave patterns measured by EEG?

we sleep in stages

Pre-sleep/sleep onset stage

When we close our eyes to relax before falling asleep, our brain slows

Stage 1 [NREM-1]

• Lightest stage of sleep from which you can be easily awakened

• May be accompanied by a dreamlike state where we experience brief hallucinatory, dreamlike images

hypnagogic sensations

This is when you may also experience that sensation of falling (at which moment, your body may suddenly jerk!) or floating weightlessly

After how many minutes of stage 1 do we descend into stages 2 and 3?

After about 30 minutes

Stage 2 [NREM-2]

• Has medium brain waves with short bursts of activity about every 15 seconds

• If/when awakened from this deep sleep, a person is groggy and confused (almost inebriated-like experience)

sleep spindles

short bursts of neural activity. May possibly be tied to memory consolation

How long does it take to go through the sleep stages?

It takes about an hour to go through the stages, then the cycle reverses itself (back to 2 & 1, then REM)

REM sleep

characterized by rapid eye activity under closed eyelids; brain waves resemble the walking state [aka paradoxical sleep]; the body also typically experiences temporary paralysis

How many trips through the sleep stages do you experience with 8 hours of sleep?

5 trips

As the night goes on which stages get shorter and which grow longer?

As the night goes on, Stage 3 sleep gets shorter and REM grows longer