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Biological Psychology > Biological Rhythms and Sleep > Flashcards

Biological Rhythms and Sleep Flashcards

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1
Q

biological rhythms

A

regular fluctuations in any living process

any biological process (including behaviour) that repeats itself at regular intervals

manifest at all levels of biological organization and extend across a wide frequency spectrum

ie/ hormone levels, body temperature and drug sensitivity - change over the course of the day in a repeating pattern

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2
Q

circadian rhythms

A

circa meaning lasts about a day 24 hrs

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3
Q

ultradian

A

less than 24 hours

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4
Q

infradian

A

less than 24 hours

repeats less than once a day

ie/ menstrual cycles

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5
Q

diurnal

A

active during the day

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6
Q

nocturnal

A

active at night

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7
Q

crepuscular

A

anything true of dawn/ dusk

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8
Q

free-running rhythms

A

removing light and dark

lost reaosn to tell rhythm to start or stop

rhythm runs out of phase

like a clock going slower, starting later and later everyday

in a dimly lit room - still displays biological clock.

in a constant light/ dark environment - not exactly 24 hours - varies a few mins

maintaining own personal cycle, in absense of external cues, bit more than 24 hrs long

every animal has its own clock differing from one another

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9
Q

endogenous clock

A

keeping time for animals is difficult without a watch to look at

in constant conditions they will still run at approximentally the same time each day

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10
Q

phase shift

A

resetting the clock by an external cue

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11
Q

entrainment

A

process of phase shifting, shifting a rhythm

synchronizing biological clock to a stimulus

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12
Q

zeitgeber

A

time giver; primary one in the sun (light)

entrains circardian rhythm

any cue an animal uses to sync its activity with the environment

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13
Q

ecological significance

A

awake and active to find food or away hiding from a predator

anticipation of events in an environment

evolutionary opportunity
can physically and behaviourally prepare before an event

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14
Q

the brains clock

A

normally synched to light and dark

after lesion animals were more active when the lights were out

continuously in dim light, behaviour was random, lesions eliminated the endogenous rhythm

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15
Q

SCN suprachiasmatic nucleus

A

what they landed on for the source of the brains clock

large lesions in the hypothalamus had an effect - eliminate various rhythms

above optic chiasm

shows rhythmic metabolic activity

rhythms in slices and in cell cultures

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16
Q

retinohypothalamic tract

A

carries info about light to the hypothalamus - veering out of the optic chiasm to synapse directly within SCN

some amphibians have a third eye - pineal gland is sensitive to light (has photoreceptors) helping circadian rhythm

in mammals severing optic nerve eliminates rhythm

direct projection of retinal ganglion cells to SCN via optic nerve = RHT

ganglion cells here contain specialized photopigment melanopsin

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17
Q

melanopsin

A

makes cells sensitive to light

if you are blind still get entrained through light because this in mice
- typically absent in blind humans
- have free running system

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18
Q

melatonin

A

pineal gland secretes at night

informs brain about day length

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19
Q

molecular foundations of the brain’s clock

A
  1. two proteins clock and cycle, bind together to form a dimer
  2. the clock/cycle dimer binds to DNA, enhancing the transcription of the genes for Period (Per) and Crypyochrome (Cry)
  3. Per and Cry bind together as a complex that inhibits the activity of the clock/cycle dimer, showing transcription of the per and cry genes, and therefore slowing production of the Per and cry proteins
  4. the Per and Cry proteins eventually break down, releasing clock/cycle from inhibition and allowing the cycle to start over again. the rates of gene transcription, protein complex formation, and protein degration result in a cycle that takes about 24 hours to complete
  5. retinal ganglion cells detect light with melanopsin and their axons in the retinohypothalamic tract release glutamate stimulation leads to increased transcription of the per gene, synchronizing (entraining) the molecular clock to the day-night cycle
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20
Q

circannual rhythms

A

seasonal cycles

for winter survival and coordinated reproduction as antipredator strategy

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21
Q

type 1 seasonal rhythm

A

endogenous/exogenous control

due to photoperiodism (melatonin duration), lesions to the SCN prevens these cycles

tract day length

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22
Q

type 2 seasonal rhythms

A

true endogenous control

SCN lesions do not affect these cycles, indicationg that there must be secondary pacemakers/ oscillators

ie/ hiberation in ground squirrels

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23
Q

EMG in sleep

A

electrode on scalp

brain potentials allow for describing levels of arousal states of sleep

eye movements and muscle tensions are also monitered in sleep

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24
Q

stage 1 sleep

A

slowing of HR
relaxation of muscles
eyes may roll slowly under eyelids

8-12 Hz

alpha rhythm - rhythm where you relax and close your eyes - time spent here decreases as drowsiness sets in

EEG has smaller amplitude and irregular frequency

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25
stage 2 sleep
sleep spindles - characteristic of 12-14 hz where a person is said to be in stage 2 sleep. occurs in periodic bursts K-complexes - a sharp negative EEG potential
26
stage 3 SWS
defined by a large amplitude and slow delta waves delta waves - slowest type of EEG about 1/sec - more prominent as night progresses brief return to stage two synchronization of cortical neuron activity pituatary releases growth hormone - prominent in early night
27
REM sleep
paradoxal sleep small amplitude high frrequency in many ways a pattern of an awkae person eyes darting rapidly under the lids irregular breathing and pulse rate experience vivid dreams 20 percent of total sleep muscles show atonia muscles relax cant be in REM when sitting in class unresponsive flaccid muscle state brainstem inhibiting motor neurons
28
atonia
complete absense of muscle tone
29
desynchronized EEG
beta activity; comprising a mix of many high frequencies with low amplitude
30
brief awakening
happens right after REM
31
Dreaming
most dreams occur REM sleep - lots of visual imagery, sense that you are there, experiencing the senses 70-90 percent of subject report dreaming in REM - tho it can occur in other stages
32
nightmares
REM long frightening dreams that awaken the dreamer
33
night terrors
sudden arousal from stages 3-4 SWS intense fear automatic activation, doesn't recall a vivid dream medication can make them more frequent common in children during early sleep
34
non- REM dreams
more the thinking type more problem, distinct difference between REM
35
babies circadian rhythms
circadian patterns of sleep evident at 16 weeks in babies - but sleep length is shorter than that of adults potentially has to do with immaturity in brain shorter in premies babies spend a lot of time in REM, premies even more - maturation of consolidation of memories activate REM sleep is muscle twitches, smiles, grimaces provides stimulation that is essential to maturation of the nervous system
36
sleep in the elderly
changes, but more slowly than in early development stages 3 decline decline in old age - 1/2 the time as they did eliminated by age 90 may relate to diminished cognitive abilities - characterized with dementia inability to maintain sleep once acheived loss of growth hormone? Loss of SWS impairs memory process total amount of sleep declines number of awakenings increases lack of sleep and insomnia is common (associated with physical and cognitive impairments) hard time staying asleep
37
effects of sleep deprivation
sleepiness! bizarre behaviour - hallucinations in some subjects deprived of approximately 8.5 days irritability, difficulty concentrating, disorientation cognitive deficits on spatial tasks reduced volume of temporal lobe depends on age and personality factors total sleep deprivation in mammals leads to death - due to hypothermia and immune system dysfunction mental function impaired sleep more to catch up 4-6 hours for 2 weeks show changes in attention, reaction time - compared to 8 hours
38
sleep recovery
performance on some tests were impaired, showed no signs of insanity stage 3 increased at expense of stage 2, but never "catches up" to the sleep deficit REM increases in intensity and recovers by night 2 sleeping more than normal after a period of sleep deprivation
39
fatal familia
an inherited disease that causes people in middle age to stop sleeping after a few months results in death
40
energy conservation
energy consumption is reduced during sleep- lowered muscle tension, lowered heart rate, reduced blood pressure, reduced body temperature, slowed respiration smaller animals with hight metabolic rates should sleep more - larger animals have lower metabolic rates and sleep less caloric savings in humans for 8 hours of sleep vs. quiet inactivity is about 120 cals (10 percent)
41
predation avoidance
environmental opportunities - for what time you are awake at - species better at different parts of the day ie/ to get food; avoiding predators sleep during the night may help reduce predation rates also allows for foraging during daylight-temporal niche REM sleep is easy to wake up from; brain waves also resemble 'awake' brain - may be periodic awakenings to check what is going on important to conform to you ecological niche; what you are well adapted to
42
body restoration
rebuild proteins used up during the day supported by sleep rebound increased metabolic demands due to high energy use during the day does not increase our length of sleep but not sleeping interferes with the immune systems and eventually leads to death (in rodents) sleep deprivation makes us more susceptable to pain the next day less than 5hrs a day more likely to develop diabetes people sleeping less or more than 8 hours more likely to die work at night, sleep in the day, more likely to develop cancer sleep cleans out the brain - glia controlling CSF are faster at night (collecting and disposing toxins)
43
consilodation of memory
why waste memory space on a dream replaying days activities and consolidating from these experiences can't learn new skills in our sleep - just helps us rememeber what we learned before we went to sleep
44
what are the 4 important neural system in sleep
forebrain, brainstem, pontine, hypothalamic
45
forebrain region
displays SWS by itself generate SWS
46
brainstem region
activates forebrain region into wakefulness
47
pontine region
triggers REM
48
hypothalamic region
regulates the other 3 systems to determine sleep or wakefulness
49
the basal forebrain
neurons become active during SWS onset actively imposes SWS on the brain inhibited by noradrenergic stimulation uses GABA to suppress tuberomammillary nucleus in hypothalamus; shuts down activity
50
Reticular formation in brainstem
wakes up cortex axons spread dispersly; project to entire forebrain electrical stimulation of reticular formation rapidy wakes animals up lesions in the RF produce persistent sleep activating system
51
the pons
triggers REM sleep - area near locus coeruleus lesions eliminate REM sleep some neurons here only seem to be active during REM sleep electrical stimultion can induce REM sleep causes atonia - though the inhibatory NT GABA causes IPSP to prevent APs - for motor neurosn flaccid muscles
52
narcolepsy
frequent, uncontrollect and intense attacks of sleep brought on by emotional experience can occur at any time usually during awaken hours can last mins to hours involves loss of muscle tone (cataplexy) and instant REM bouts enter REM within a few mins exhibit a normal sleep schedule at night orexin is crucial
53
where does the hypothalamus project to, to release orexin
pons basal forebrain reticular formation tuberomamillary nucleus
54
cataplex
sudden loss of muscle tone, leading to colapse of the body without loss of consciousness can be triggered by intense emotional stimuli
55
orexin
neuropeptide made in hypothalamus that is involved in switching between sleep states
56
Somnambulism
sleep walking more common in children amnesia for experience occur in stages 3 and 4 occasionally seen in murder and rape cases
57
REM behaviour disorder
organized sleep walking; fighting a Foe, eating a meal, acting like an animal may be acting out a dream more common in men follwed by parkinsons and dementia
58
sleep enuresis
bed wetting associated with SWS
59
insomnia
inability to fall asleep, 15-30 percent adults more prevalent in females, smokes, alcoholic and caffeine users multiple causes - medical conditions, first night effect, shift work sleep onset and sleep maintanence sleep apnea
60
sleep onset insomnia
difficulty falling asleep
61
sleep maintenence insomia
drugs seem to cause
62
sleep apnea
breathing ceases blood levels of oxygen drop arises from progressive relaxation, changes in pacemaker
63
sleep-state misperception
not even sleeping when EEG showed signs of sleep sleeping without knowing it

Biological Psychology (6 decks)

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