Biological Rhythms and Sleep
Studied by 0 people
Call Kai
Learn
Practice Test
Spaced Repetition
Match
Flashcards
Knowt Play1/95
There's no tags or description
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced |
|---|
No study sessions yet.
96 Terms
biorhythm
inherent timing mechanism that controls or initiates various biological processes; linked to the cycle of days and seasons produced by the Earth’s rotation around the sun.
period
time required to complete a cycle of activity.
circadian rhythms
those functions of a living organism that display a rhythm of about 24 hours.
diurnal
active during the light.
nocturnal
active during the dark.
ultraradian rhythms
period of less than a day (length can be from minutes to hours).
ex. bouts of activity, feeding, hormone release
infradian rhythms
period of more than a day (monthly or seasonal).
ex. body weight, reproductive cycles
circannual rhythms
period of about a year.
ex. migratory cycles of birds, fur changes in siberian hamsters
endogenous
Behavior is not simply driven by exogenous or external cues from the environment because rhythms are _____ (control comes from within).
biological clock
neural system that times behavior; allows animals to anticipate events before they happen.
ex. birds migrate before it gets cold
free-running rhythm
rhythm of the body’s own devising in the absence of all external cues.
25 to 27 hours, 24.1-24.2 hours
without input from external cues, our bodies have their own rhythms with periods of ____.
the human sleep-wake cycle shifts an hour or so everyday.
BUT, when light, eating times, and sleep times are given then rhythm moves to _____.
sleep-wake cycle
temperature
hormones
what are 3 examples of our body’s processes that involve rhythmic daily fluctuations?
free-running animal
animal that maintains its own cycle without external cues.
entrainment
the process of shifting the rhythm.
zeitgeber
the cue that an animal uses to synchronize with the environment; German for “time-giver.”
sleep
___ is synchronized to external events, including light and dark.
Stimuli like lights, food, jobs, and alarm clocks entrain us to be awake or to sleep.
staying up late in artificial light
night shift workers
jet lag
(linked to immune deficiency and metabolic syndromes caused by hormonal changes in mood and temperature)
what are 3 examples of disruptions to biological rhythms?
jet lag
fatigue and disorientation from rapid travel through time zones and exposure to a changed light-dark cycle.
after, before
melatonin therapy…
when traveling eastwards/advance, administer melatonin ___ the normal peak.
when traveling westwards/delay, administer melatonin ___ the normal peak.
suprachiasmatic nucleus (SCN)
main pacemaker of circadian rhythms located just above the optic chiasm.
retina, pineal gland
Other pacemakers exist in the ___ and ____, but the SCN is the main one.
retinohypothalamic tract
regulates circadian rhythms and the pupillary reflex via melanopsin-containing RGCs.
…the rhythmic nature of these behaviors disappears.
…reestablish circadian rhythms.
transplantation studies in hamsters…
after lesions to the SCN, hamsters eat and sleep a normal amount, but…
If SCN cells from embryos are transplanted into the lesioned animals, they will...
light, dark
light, dark
Metabolic activity of the SCN is higher during the ___ (light/dark) period of the day-night cycle than it is during the ___ (light/dark) period of the cycle.
Neurons in the SCN are more active during the ___ (light/dark) period of the cycle than during the ___ (light/dark) period.
pathways
Neurons in the SCN maintain their rhythmic electrical activity even when all ____ into and out of the SCN are cut.
Isolated SCN neurons can maintain electrical activity synchronized to the previous light cycle.
pineal gland
In amphibians and birds, the ____ is sensitive to light.
retinohypothalamic pathway
In mammals, light information goes from the eye to the SCN via the ____.
retinal ganglion cells that project to the SCN
do not rely on rods and cones
most contain melanopsin, a special photopigment that makes them sensitive to light, especially blue light
melanopsin
a special photopigment that makes retinal ganglion cells sensitive to light (especially blue light).
period (per)
Molecular studies in Drosophila using mutations of the ____ gene helped to understand the circadian clock in mammals.
clock
cycle (called Bmal1 in mammals)
what 2 proteins do SCN cells in mammals make?
clock and cycle proteins bind together to form a dimer.
the clock/cycle dimer promotes transcription of period (per) and cryotchrome (cry) genes
per and cry proteins then dimerize
the per/cry protein complex enters the nucleus and inhibits the transcription of the clock/cycle genes
no new clock/cycle proteins are make until the per/cry proteins degrade; the cycle takes approximately 24 hours.
what is the role of clock and cycle in the circadian clock?
directly, degrades
In flies, light reaches the brain ____ and ____ the Cry protein, synchronizing the molecular clock.
glutamate
In mammals, retinal ganglion cells detect light and release ____ in the SCN. Glutamate triggers events that promote Per protein production, which then shifts the clock and the animal’s behavior.
slave oscillators
SCN pacemaker drives a number of ______, each of which controls the rhythmic occurrence of one behavior.
pituitary endocrine neurons
The SCN connects with the ______ to influence hormone release (glucocorticoids from adrenal gland in light phase).
pineal gland
SCN controls melatonin release from the ____ (sleep, and rest/digest response).
winter, summer
in hamsters…
In ____, melatonin levels decrease, gonads shrink, testosterone levels decrease, and sexual behavior decreases.
In ____, melatonin levels increase, gonads grow, testosterone levels increase, and sexual behavior increases.
basic rest-activity cycle (BRAC)
recurring cycle of temporal packets, about 90-minute periods in humans, during which an animal’s level of arousal waxes and wanes.
electroencephalogram (EEG)
record of brain-wave activity.
electromyogram (EMG)
record of muscle activity.
electrooculogram (EOG)
record of eye movements.
W (waking)
N1 (NREM stage 1)
N2 (NREM stage 2)
N3 (NREM stage 3)
R (REM)
what are the 5 stages of sleep?
waking
beta rhythm = awake
alpha rhythm = relaxed
what are some characteristics of W sleep?
sleep onset
theta rhythm
what are some characteristics of N1 sleep?
theta rhythm
regular brain waves (4-11 Hz).
asleep
sleep spindles and k complexes
what are some characteristics of N2 sleep?
deep sleep state
delta rhythm
what are some characteristics of N3 sleep?
delta waves
slow, large brainwave activity (1-3 Hz) pattern associated with deep sleep.
dreaming state
fast brainwave pattern displayed by the neocortical EEG record during sleep
what are some characteristics of REM sleep?
alpha rhythm
brainwave activity that appears during relaxation, regular oscillation at 8-12 Hz.
vertex spikes
Stage 1 sleep begins when ____ appear.
Heart rate slows, muscle tension decreases, eyes roll about.
Lasts several minutes.
sleep spindles, k-complexes
Stage 2 sleep is defined by waves of 12-14 Hz that occur in bursts called _____. Then, ____ appear– sharp negative EEG potentials
slow-wave sleep (SWS)
NREM 3, or ____ is defined by the appearance of large-amplitude, very slow waves called delta waves.
delta waves occur about once per second
by late stage 3 sleep, delta waves dominate
EMG (muscle) activity, but no EOG (eye) activity.
EMG (muscle), EOG (eye)
In NREM 3 sleep, there is ____ activity but no ____ activity.
decrease in body temperature
increase in growth hormone release
dreaming (less vivid than REM sleep)
sleeptalking
sleepwalking
night terrors
what are some activities that occur during NREM sleep?
paradoxical sleep
REM sleep is sometimes called _____ due to the mismatch between brain activity that resembles an awake person and the lack of muscle activity (no EMG activity).
atonia
no tone; condition of complete muscle inactivity produced by the inhibition of motor neurons.
body temperature, vivid dreams
During REM sleep, mechanisms that regulate ____ stop working, and ____ occur.
longer
REM periods get ____ throughout the sleep cycle (5 total in 7 hours).
first half of sleep– NREM dominant
second half of sleep– REM dominant
wakefulness
There are brief periods of ____ after each REM cycle, and you feel more rested if you get up during one of these natural awakenings.
sleep cycle
a period of slow-wave sleep followed by one of REM sleep; 90-110 minutes for humans.
REM
In infants, more time (about 50%) is spent in ___ sleep, which may provide essential stimulation to the developing nervous system.
7-8, 40-50%, 20%
In a typical night of young adult sleep, sleep time ranges from ___ hours, ___ is stage 2 sleep, and ___ is REM sleep.
stage 3
As people age, total time asleep declines, and the number of awakenings increases.
The most dramatic decline is in the loss of time spent in ___.
At age 60, only half as much time is spent in stage 3 as at age 20; by age 90, stage 3 has disappeared.
R-sleep, N-sleep
Vivid dreams that we remember occur during ____.
Less vivid dreams (except for night terrors) occur during ____.
sigmund freud’s psychoanalytic theory
believed dreams are the symbolic fulfillment of unconscious wishes and have different levels of meaning.
dreams dreams deal with childhood events, anxiety, and wish fulfillment.
carl jung’s psychoanalytic theory
believed dreams are expressions of our collective unconscious (history of the human race) lost to conscious awareness.
quite recent events
Most dreams are related to ____ (80%) and concern ongoing problems.
bottom-up approach to dreaming
a person has a dream, then either the dreamer or a dream interpreter analyzes it.
top-down approach to dreaming
dreamer makes the dream as a coping mechanism.
activation-synthesis theory
cortex is bombarded with signals from brainstem, producing the pattern of waking EEG.
in response, the cortex generates images, actions, and emotions from personal memory stores.
in the absence of external verification, these dreams are fragmented and bizarre, revealing nothing more than that the cortex has been activated.
dreams are persona: memories and experiences are activated, but they have no meaning.
evolutionary hypothesis
dreams are biologically important, highly organized, and biased toward threatening images.
approach, avoidance
Malcolm-Smither and colleagues noted that…
____ behavior occurs more frequently in dreams than ____ behavior.
Reward-seeking behavior is as likely to represent a dream’s latent content as avoidance behavior is.
lucid dreams
awareness of dreams as they are dreamed.
occur infrequently for some people, or several times a week by others.
two-theory of consciousness
core and global consciousness systems ordinarily sleep together.
occasionally the global consciousness system awakens and becomes an observer of the dream produced by the core consciousness system.
contrasting states of these two consciousness systems are experienced as lucid dreaming.
sleep is a passive process
sleep is an energy-conserving strategy
what are 2 things we used to believe about sleep?
sleep enforces niche adaptation
sleep is a restorative process
sleep aids memory consolidation
what are the main 3 biological functions of sleep?
avoid predators
Sleep helps animals ____; animals sleep during the part of the day when they are most vulnerable.
ecological niche
Being nocturnal or diurnal is part of an animal’s ____, that unique assortment of environmental opportunities and challenges to which each organism is adapted.
metabolic
Sleep restores the body by replenishing ___ requirements, such as proteins.
growth
Most ___ hormones are released during SWS.
waste products
During sleep, glia flush ____ faster than when awake.
declarative, nondeclarative
Sleep improves ____ memory, and REM sleep may help consolidate ____ memory. Sleep deprivation increases the likelihood of creating false memories.
sleep deprivation
the partial or total prevention of sleep; effects include increased irritability, difficulty concentrating, and episodes of disorientation.
fatal familial insomnia
inherited disease in which people stop sleeping in midlife and die 7-24 months after onset of insomnia.
autopsy shows degeneration in the brain.
sleep recovery
the process of sleeping more than normal after a period of deprivation.
stage 3 sleep is increased, usually at the expense of stage 2 sleep
what happens during night 1 of sleep recovery?
most recovery of REM sleep, which is more intense than normal with more rapid eye movements
what happens during night 2 of sleep recovery?
sleep memory storage theory
memory storage theory that hypothesizes that the brain makes a rendition of a memory that is replayed during sleep.
recording the brain’s electrical events reveals when memory replay is occurring.
synaptic homeostasis memory theory of sleep
memory storage theory that hypothesizes that the brain undergoes global changes during sleep that allows the biochemical events associated with memory storage to occur.
place cell
hippocampal neuron that fires when a rat is in a certain location in an environment.
food-searching task
In rats, groups of place cells that fired during a ___ also fired during the subsequent sleep period.
serial reaction time task
pierre maquet and colleages (2000) used PET imaging to record brain activity while human subjects performed a ____.
PET imaging during subsequent sleep revealed that the same brain regions that were active during the task were also active during REM sleep.
subjects were dreaming about their learning experience, and REM sleep strengthened the memory of the task!
repetition
The ___ of the waveforms may be the signature of memory replay and the transfer of memory between forebrain structures.
store memory during wakefulness
Although evidence shows that memory strengthens during sleep, less clear is whether the neural and molecular changes that support sleep memory storage resemble those that ____.