Overview Flashcards
(32 cards)
Circadian Rhythms
Biological rhythms that last “about a day”. (Are usually >24 hours, due to the need to reset and adjust to fit the 24 hour rotation of the Earth, hence why zeitgebers are important)
Diurnal
Active during the day (light periods)
Zeitgebers
(German: “time giver”) - cues from the environment used to entrain an animal’s circadian rhythm
(sunlight is the most effective zeitgeber for humans)
Entrainment
The process of synchronizing one’s biological rhythm to a cue in the environment.
An example would be adjusting how much you sleep.
When lighting is constant however (no night), the hamster goes to sleep and wakes up at ____
Roughly the same time so circadian behavior is influenced by light/dark, but not totally.
Demonstrates free-running rhythms
Suprachiasmic nucleus (SCN)
The brain has a biological clock with 24-hour periodicity, the _____
The SCN releases chemicals that affect
- Lower body temperature
- Lower blood pressure
- Digestion
We stick to circadian rhythms because of the internal biological clock, known as the _____ and external cues, known as
Suprachiasmic nucleus (SCN); zeitgebers
The _____ send messages to the SCN to tell when it’s light or when it is dark.
Optic nerves
Photopigment within certain retinal ganglion cells that project to the SCN. Does not mediate vision, but tells SCN whether it is light or dark.
Not for vision but for entrainment.
Melanopsin
When it is light, melanopsin containing retinal ganglia ____ hormone release by the SCN
Inhibit
When it is dark, melanopsin containing retinal ganglia set-off a chain reaction, ultimately causing the Pineal gland to release a hormone called _____
Melatonin
Brain recording using _____ enables researchers to observe the brain’s behavior/activity, even without the participant having to be awake
Electroencephalogram (EEG)
There are 4 distinctive stages of sleep, and one additional type of sleep that occurs during stage 1, called ______ sleep.
Rapid Eye Movement (REM)
Awake/alert
- fast (13-30 Hz, beta)
- low amplitude EEG waves
- very small and fast
- beta has the smallest peaks
- decent amount of mental activity
Eyes closed, relaxed
- slower (8-13 Hz, alpha)
- higher amplitude EEG waves
Stage 1
Stage ___ has even slower (4-8 Hz, theta), low amplitude EEG waves
Stage 2
Stage ___ is where EEG looks like stage 1, punctuated by K-complexes and sleep spindles
Stages 3 & 4
Stage _ & _ have slow-wave sleep (SWS) characterized by predominantly high amplitude delta (1-4 Hz) rhythms
Non-REM (NREM)
- Initial stage 1 and stages 2-4 without REM are called _____. The EEG during REM sleep looks like the EEG during wakefulness.
Down-states; theta and delta
Stage 2 K-complexes reflect neuronal __ and lead to ___ and ___ waves in slow-wave sleep (SWS) in stages 3 and 4
Postsynaptic potentials (PSPs)
Neurons like to have resting _____ that are either “up” (slightly depolarized, ready for action potential) or “down” (slightly hyperpolarized, silent and not ready to fire an action potential)
Thalamus
When cortical neurons are in “down-states”, they are less receptive to input from the _____. In other words, these down-states inhibit sensory input/arousal.
Motor pathways
Most are inhibited during REM to prevent a person from acting out his or her dreams (therefore sleepwalking or sleep talking cannot occur during REM)
