Biopsychology (paper 2) Flashcards

Question

What are nodes of ranvier?

Answer 1

-the *gaps between the myelin sheath* -Their purpose is to *speed up the transmission of the impulse*, by *forcing it to 'jump' across the gaps* along the axon.

Answer 2

-also called *axon terminal* -*located at the end of the axon* -*communicate with the next neuron* that is on the other side of the synaptic cleft.

Answer 3

-process by which *neighbouring neurons communicate* with each other by sending *chemical messages across the synaptic cleft* them separates them.

Answer 4

-*Brain chemicals released from synaptic vesicles* that *relay signals across the synapse* from one neuron to another -can be broadly divided into those that perform an *inhibitory or an excitatory function*

Answer 5

-when a *neurotransmitter*, (ie adrenaline), increases the positive charge of the postsynaptic neuron* -This *increases the likelihood that the neuron will fire* and pass on the electrical impulse.

Answer 6

-When a *neurotransmitter*, (ie serotonin), makes the *change of the postsynaptic neuron more negative* -This *decreases the likelihood that the neuron will fire* and pass on the electrical signal.

Answer 7

-*junction between two neurons* -includes the presynaptic neuron, the synaptic clef and the postsynaptic receptor site.

Answer 8

-The *space between the pre-synaptic and post-synaptic neuron*

Answer 9

-*Small sacs on the end* of a presynaptic neuron that *contain neurotransmitters* that will be released into a synapse.

Answer 10

-*transmitting neuron*, before the synaptic cleft.

Answer 11

-*neuron that is receiving the information* at the synapse.

Answer 12

-*receptor on the post-synaptic neuron.* -*neurotransmitter locks into a specific receptor* on the post-synaptic neuron and this *triggers an electrical impulse* in the post-synaptic neuron.

Answer 13

1) *Action potential* (electrical impulse) arrives at *pre-synaptic neuron* 2) as a result of the action potential, *vesicles* (containing neurotransmitters) *diffuse towards the pre-synaptic membrane* 3) *Vesicles bind* to the pre-synaptic membrane and the *neurotransmitters are released* 4) Neurotransmitters *chemically diffuse across* the synapse (electrical impulse becomes chemical impulse) 5) Neurotransmitters *bind to complementary receptors* on the post-synaptic neuron membrane and an *electrical impulse is subsequently passed on*

Answer 14

-*chemical messengers* that relay signals, diffuse across the synapse and *elicit an effect* -ie serotonin, GABA

Answer 15

-*synaptic vesicles* containing neurotransmitters are *only on* the *pre-synaptic membrane* and the *receptors* are *only on* the *post-synaptic membrane*

Answer 16

-*all parts* of the brain are *involved in* the processing of *thought and action*

Answer 17

-*specific areas* of the brain are *associated* with *particular physical and psychological functions* -*damage* to these areas cause *consequences in behaviour*

Answer 18

-the *detailed study* of the *shape and size* of the *cranium* as a supposed *indication of character and mental abilities*

Answer 19

-*central core* (or the brain stem -inc structures such as the hypothalamus in the midbrain, regulates our *most primitive and involuntary behaviours* (ie breathing, sleeping or sneezing) -*limbi system* controls our *emotions* -*around the central core* of the brain. -inc structures such as the hippocampus which has a key role in *memory* -*cerebral cortex* is the third layer -*divided into two hemispheres*; the left hemisphere and right hemisphere. -cortex is about *3mm thick* and is what *separates us from other animals* because the human cortex is *much more developed* -both hemisphere is *subdivided into four lobes* (named after bones they lie beneath: the frontal, the parietal, the occipital and the temporal lobe) -*Each lobe is associated* with a *different function*

Answer 20

-*back of frontal lobe* -sends *nerve impulses to muscles*, different areas control different muscle movements -*damage* results in *loss of muscle movement*

Answer 21

-*front of parietal lobe* -*processes sensory information* from the skin (ie pressure, heat, touch) -*damage* results in *loss of senses*

Answer 22

-occipital lobe -receives and *processes information* from *optic nerve* -*damage* results in *loss in visual field*

Answer 23

-*temporal lobe* -to *analyse speech based information* -*damage* results in *loss in hearing*

Answer 24

-*left temporal* lobe -responsible for *speech comprehension* -*damage* results in *difficulties understanding speech* (Wernicke’s aphasia)

Answer 25

-*left frontal* lobe -responsible for *speech production* -*damage* results in *difficulties to speak and write* (Brocas aphasia)

Answer 26

-located *within specific areas* of the brain. Broca - frontal lobe Wernicke - temporal lobe -But they *only occur in the left hemisphere* -makes them "special". (something *specialised to one hemisphere*, is known as *lateralisation*)

Answer 27

Strengths -*brain scanning evidence* Petersen et al (1988) used brain scans showed Wernicke’s area-active during listening task and Broca’s area-active during reading task, suggests these parts of the brain have different functions, support Wernicke/Broca’s theories increases validity of concept of localisation -*neurosurgical evidence* Dougherty et al. (2002) reported on 44 OCD patients who had cingulotomy (cingulate gyrus is lesioned), 32 weeks post-surgery, showed third of patients had successful response to surgery and 14% a partial response suggests symptoms/behaviours associated with OCD are localised -*case study evidence* Phineas Gage accident left his frontal lobe damaged, his personality changed (to quick-tempered and rude) suggests personality/temperament is localised within the frontal lobe Limitations -*evidence for some higher cognitive functions distributed in a holistic way* Lashley (1950) removed areas of the cortex (between 10 and 50%) in rats, No area proved more important than another in rat’s ability to learn a maze, suggests learning is too complex to be localised and involves the whole brain -*Functional recovery shows localisation of function can change* girl lives with only half a brain as after illness/accident, rest of the brain appears to reorganise itself in an attempt to recover lost function, supports holistic view of functioning

Answer 28

-works by *detecting changes in blood oxygenation and blood flow* that *indicate increased neural activity* -It produces *3-dimensional images* (activation maps) shows *parts of the brain are involved* in *particular mental process* (important for establishing localisation of function) -People *do a task* and it is *observed where the brain activity is* -When a *brain area is more active* it *consumes more oxygen* and to meet this increased demand *blood flow is directed to the active area* (*haemodynamic response*).

Answer 29

Strengths -*non-invasive* (unlike PET scans) -*doesn’t rely on the use of radiation* and is safe. -*high spatial resolution*. It can show detail by the millimetre. provides clear picture of localised brain activity Limitation -*expensive* compared to other techniques -*only capture an image* if the *person stays still* -*poor temporal resolution* as there is a 5 second lag between initial neural activity and image so may not truly represent moment-to-moment brain activity

Answer 30

-records *changes in electrical activity* using electrodes attached to thescalp. -The *scan recording* represents the *brainwave patterns* that are generated *from the action of millions of neurons*, providing an overall account of brain activity. -often used as a *diagnostic tool* as *unusual arrhythmic patterns* may indicate *neurological abnormalities* e.g. epilepsy.

Answer 31

Strengths -*invaluable in diagnosing conditions* (been used to identify epilepsy and also in understanding the stages of sleep) -*extremely high temporal resolution* detect brain activity as a *resolution of a single millisecond*, So its more able to represent *moment-to-moment brain activity* Limitation -produces a *generalised signal from thousands of neurons *this means it’s *difficult to know the exact source* of neural activity, it cannot distinguish between the activity of different but adjacent neurons. -do *not provide a complete picture* of brain activity. They *only monitor* electrical activity on *outer layers of brain* so cannot reveal electrical activity deeper in the brain

Answer 32

-records *changes in electrical activity* using electrodes attached to the scalp but *uses a specific stimulus* (sensory, cognitive or motor) to see where the activity is. -Using a *statistical averaging technique*, all *extraneous brain activity* from the original EEG recording is *filtered* out *leaving only those responses that related to a specific stimulus* or task. -Research has *revealed many different forms of ERP* and how these are *linked to cognitive processes*

Answer 33

Strengths -*very specific measurement* of neural processes. More specific the raw EEG data -*excellent temporal resolution*,can detect brain activity as a *resolution of a single millisecond*. So able to represent *moment-to-moment brain activity* Limitation -*lack standardisation in methodology* between studies. So its *difficult to confirm findings in studies* involving ERPs. So *reliability* of the information regarding the brain's structure and function is *lowered* -*background noise and extraneous material must be completely eliminated* which is *not easy*to acheive

Answer 34

-*examine abnormalities* in the *structure of the brain* which try to *explain psychological abnormalities* that people have before death -*may also involve comparison* with a *neurotypical (normal) brain* in order to ascertain the extent of the difference.

Answer 35

Strengths -provided the* foundation for understanding the brain* (Broca and Wernicke both relied on them) shows they have *improved medical knowledge* and helped to *generate hypotheses* for further study. -allow for *in-depth study* of the brain. *Detailed examinations and measurements of deep brain structures* that are not measurable by scans. Provides knowledge of brain that cannot be gained from less invasive options. Limitations -*causation may be an issue*, *Observed damage* in the brain may *not be linked to the deficits* under review *but* some other related to *trauma or decay* -raise *ethical issues of consent* Before death, patients *need to give informed consent*, but there is a *reason that psychologists want to investigate their brains* in the first place *may mean they are not be able to provide informed consent* (eg HM lost ability to form memories so couldn t provide consent)

Answer 36

-meter long *iron pole* went through his left cheek passed behind left eye, and exited his skull at top of head *took portion of his brain* with it – most of his *left frontal lobe* -he *survived* but the damage to his brain *left a mark on his personality* (turned from calm/reserved to quick-tempered/rude and ‘no longer Gage’) -seen as a *landmark case in science* the change in temperament *suggests the frontal lobe* may be responsible *regulates mood*

Answer 37

Strength -*brain scanning evidence*, Petersen et al (1988), brain scans demonstrated *Wernicke’s area active during listening task, Broca’s area active during reading task. suggests these parts of brain have different functions support *Wernicke and Broca’s theories increases the validity* -*neurosurgical evidence*, Dougherty et al (2002), *44 OCD patients* who had *undergone a cingulotomy* (procedure where the cingulate gyrus is lesioned). post-surgical *32 week follow-up* showed *third of patients* had a *successful response* to the surgery and *14% a partial response*, suggests that *OCD symptoms/behaviours are localised* Limitations -*evidence* suggests some *higher cognitive functions distributed* in a more holistic way, Lashley (1950) *removed areas of the cortex* (between 10 and 50%) *in rats* learning a maze. *No area was proven to be more important* in rat’s ability to learn the maze, suggests *learning is too complex to be localised* and involves the whole brain -*Functional recovery* shows *localisation of function can change*, girl who *lives with only half a brain* after illness/accident the rest of the *brain appears to reorganise itself in attempt to recover lost function*, supports that the *holistic view of functioning rather than localisation*

Answer 38

*Some mental processes* in the brain are mainly *specialised to the left or right hemisphere* e.g. Language is specialised to the left and visual-motor tasks.

Answer 39

This means the *opposite side* of the body to the brain hemisphere that controls it.

Answer 40

*Broad band of fibres* that *joins the two hemispheres* of the brain, this*allows communication* to occur.

Answer 41

-*cutting of the corpus callosum* means that *information cannot be passed between* the hemispheres.

Answer 42

Aim: -to *examine the extent* to which the *two hemispheres are specialised* for certain functions. Participants: -Studied *split brain patients* and *compared* them to *patients with no hemisphere separation* -*11 participants* (epileptics who couldn’t be treated with drugs and ALREADY HAD their corpus callosums split to control frequent fits) Method: -*image/word is projected to the patient’s left visual field* (processed by the right hemisphere) or vice versa. When *information is presented to one hemisphere* in a split- brain patient, the *information not transferred to other hemisphere*

Answer 43

Drawing -*right hemisphere could draw* the word ‘saw’, but *not say it*. suggests right is *dominant drawing skills* tactile objects -*right hemisphere* could also *get left hand to pick up correct object from selection of objects* facial recognition -*right hemisphere* was found to be *better at recognising faces*

Answer 44

findings of Sperry and Gazzaniga’s research highlights *key differences between the two hemispheres* -*left* hemisphere is dominant in terms of *speech and language* -*right* hemisphere is dominant in terms of *visual-motor tasks* -*split brain patients* their *hemispheres* of the brain *process information separately* -*Hemispheres* do seem to *have differing functions* (e.g language left and drawing ability right)

Answer 45

Strengths -*no ethical issues*, patients already had procedure done for seizures, so no harm or deception -*strong methodology* experiments had standardised procedure aka patients asked to stare at fixation point one eye blindfolded and image flashes on screen shortly. Ensures one hemisphere received info. Sperry had a controlled and useful procedure Limitations -*small sample*, 11 participants so limits generalisability. patients epilepsy may have influenced findings, control group made of people with no epilepsy history (inappropriate?) -*artificial tasks* patients stare at x on screen and cannot move heads, real life they can move/use both eyes. So research lacks mundane realism. -sample size had *both genders* evidence shows there are gender differences in lateralisation of function, not clarified in this study -- limits generalisability.

Answer 46

The brain’s tendency to change and adapt (functionally and physically) as a result of experience and new learning.

Answer 47

As we age, rarely used connections are deleted and frequently used connections are strengthened

Answer 48

Undamaged axons grow new nerve endings to reconnect neurons whose links were injured or severed.

Answer 49

-where *new connections are created* due to use and new stimulus -During infancy the brain experiences a growth in the number of synaptic connections peaking at 15,000 at age 2-3 years. -This is twice as many as there are in the adult brain!

Answer 50

-where *connections are lost* due to lack of use. -As we age, rarely used connections are deleted and frequently used connections are strengthened (synaptic pruning)

Answer 51

-originally thought such changes were restricted to the developing brain within childhood as the adult brain had moved beyond a critical period, so would remain fixed/static in terms of function and structure. -However, research suggests that at any time in life existing neural connections can change, or new neural connections can be formed because of learning and experience.

Answer 52

Aim: *examine* whether *structural changes* could be detected in the brain of *people with extensive experience of spatial navigation* Method: *MRI scans* comparing 16 male London Taxi drivers and 50 age-matched male control subjects who did not drive taxis (part of their training, London cabbies must take test called ‘The Knowledge’ to assess recall of the city streets and possible routes, This learning experience appears to alter structure of the taxi driver’s brains)

Answer 53

-drivers had *significantly larger posterior hippocampi* than control group (posterior hippocampus associated to development of spatial and navigational skills/memory) -*positive correlation* between *size of posterior hippocampus and the time as a taxi driver* (Correlation not causal but implies experience of taxi driving changes brain/hippocampus)

Answer 54

-results provide *evidence for structural differences* between hippocampi London taxi drivers and control participants, *suggests extensive practice with spatial navigation affects the hippocampus*. (extensive training required to learn the layout of London’s streets)

Answer 55

-a *form of plasticity* -*Following trauma damage*, the brain can *redistribute or transfer functions* (usually performed by damaged area to undamaged area) -*brain learns to COMPENSATE for the area that has lost the function* -process can *occur quickly* (*spontaneous recovery*) and *then slow* after several weeks or months. -At this point the *individual may require rehabilitation therapy* to further their recovery.

Answer 56

-Through the *law of equipotentiality* (secondary neural circuits surrounding the damaged area become activated) -*brain rewires and reorganises* itself by forming new synaptic connections close to the area of damage -Secondary neural pathways that would not typically be able to carry out certain functions are activated or ‘unmasked’ to enable functioning to continue (AKA neural activation of ‘dormant’ synapses to compensate for damaged areas of the brain)

Answer 57

1. *Axonal sprouting* (growth of new nerve endings, connect with other undamaged nerve cells to form new neuronal pathways) 2. *Neural reorganisation* (transfer of functions to undamaged areas) 3. *Reformation of blood vessels* (part of haemodynamic response, where activated areas experience a higher blood deoxygenation level) 4. *Recruitment of homologous* (similar) areas on opposite side of brain perform specific tasks. (E.g Damage to Broca’s area on the left could mean right-side equivalent would carry out its functions temporarily)

Answer 58

-Plasticity (neuroplasticity/cortical remapping) describes the brains tendency to change and adapt (functionally and physically) as a result of experience and new learning. WHEREAS… -Functional recovery is a form of plasticity. Following damage through trauma, the brain has the ability to redistribute or transfer functions usually performed by a damaged area(s) to other undamaged area(s).

Answer 59

• How much people want to recover • How tired people are • How stressed people are • How much alcohol/drugs people are having • Age - younger individuals recover more quickly • Gender - women recover more quickly • Educational attainment - research has found those with a college degree are more likely to recover faster than those who did not finish high school

Answer 60

Strengths -*case study support*, Danelli et al., (2013) describes boy had entire left hemisphere removed age 2 1/2 where language function primarily localised and boy initially unable to speak. But language skills recovered after 2 years. suggests right hemisphere adapted take over function. -*Supporting research*, Tajiri et al (2013) evidence for role of stem cells in recovery from brain injury, randomly assigned rats with traumatic brain injury to one of 2 groups. One group received transplants of stem cells to region of brain affected by injury, control group received a solution infused into brain containing no stem cells. 3 months after brain injury, stem cell rats showed clear development of neuron-like cells in the area of injury, accompanied by a solid stream of stem cells migrating to the brain’s site of injury. not the case with the control group -*practical application* Following illness:injury to brain, spontaneous recovery slows down so forms of physical therapy may be required to maintain function improvements (eg movement therapy and electrical stimulation of brain to counter deficits in motor or cognitive functioning. Understanding processes involved in plasticity contributed to field of neurorehabilitation. Limitations -*individual differences in functional recovery* Schneider et al. (2014) discovered the more time brain injury patients had spent in education, (taken as indication of their ‘cognitive reserve’), the greater chances of a disability-free recovery. shows that educational attainment may influence how well the brain functionally adapts after injury -*Plasticity can have maladaptive consequences* 60-80% of amputees develop phantom limb syndrome (the continued experience of sensations in the missing limb as if it were still there), sensations are unpleasant/painful due to cortical reorganisation in somatosensory cortex occurs as result of limb loss

Answer 61

-*cyclical changes* (go in a cycle) in the way that the our biological systems behave. • Circadian – 24 hour cycles • Infradian– over 24 hour cycles • Ultradian – less than 24 hour cycles -evolved because the environment which we/other organisms live has cyclical changes: • Day and night • Summer and winter

Answer 62

-*Endogenous pacemakers* internal body clocks that regulate many of our biological rhythms (eg influence of suprachiasmatic nucleus (SCN) on the sleep-wake cycle) -*Exogenous Zeitgebers* external cues that may affect or entrain our biological rhythms, (eg influence of light on sleep-wake cycle)

Answer 63

-any cycle that *lasts about 24 hours* -These rhythms optimise an organism’s physiology and behaviour to best meet the varying demands of the day and night cycle. -The rhythm is regulated by an internal system such as the release of hormones, metabolic rate and body temperature. -There are numerous examples of circadian rhythms: • Sleep/wake cycle • Melatonin production • Regulation of body temperature

Answer 64

-Light/dark provide signals of we should be awake and asleep. -Our strongest sleep drive occurs between 2 - 4 am and 1 - 3 pm (post lunch). Sleepiness is less intense with circadian dips if we have had enough sleep the night before. -Homeostasis also controls need to sleep, need more energy body tells us to sleep (why we get more tired the longer we have been awake) -These factors combine to control/allow us to sleep during the night and be awake during the day. -However, the effect of daylight (exogenous zeitgeber) has an important effect on when we feel drowsy and awake.

Answer 65

-He wanted to prepare a geological expedition but decided instead to live without a watch while underground -investigated what would happen to people’s circadian rhythms if they were cut off from all signals from outside the body that tell us about the time of day (such as light and dark, clocks), and had to rely on internal body clock to tell them to eat/sleep.

Answer 66

-descended into a *cave* on July 16th 1962, completely *devoid of natural light* -stayed there for *63 days* (came out September 14th) -called his team when he woke, ate and before sleep, they couldn’t call him so he wouldn’t know the time -when his team called him he took his pulse and did 'psychological test' (counted from 1 to 120 seconds)

Answer 67

-showed humans have a biological clock (his clock was allowed to 'free-run', he followed his body's inclinations, eating and sleeping whenever he chose, with no fixed timetable) -He was wired up so that some of his body functions could be recorded; a telephone link to the outside world, and monitored by video camera. -during ‘psychological test’ it took him 5 minutes to count to 120, he experienced 5 minutes as if it were 2

Answer 68

-*prolonged exposure to a strong exogenous zeitgeber* (eg light), the *sleep-wake cycle is disrupted* and there’s disconnection between psychological time and the clock. -His sleep-wake cycle *did not conform to a cyclical 24 hour-period*, but around 24 hours and 30 minutes -Therefore, demonstrateing that there is an internal biological clock. This describes a ‘free-running’ circadian rhythm i.e. one which is not affected by exogenous zeitgebers.

Answer 69

Strengths -*research has practical application* circadian rhythms coordinate body’s basic cycles, has implications for pharmacokinetics (action of drugs on body and how well they’re absorbed/distributed, times during day/night when drugs are more effective Guidelines developed for the timing of dosing for a range of drugs including treatments for cancer and epilepsy. -lack of ethical concerns as Siffre carried out experiment on himself, of his own free will -*High reliability* studies support natural light impacting on circadian rhythm (Aschoff and Wever (1976) placed participants in an underground WWII bunker with artificial light, no natural light and complete lack of environmental/social cues for 4 weeks. most participants settled into a sleep/wake cycle between 24 and 25 hours, (some were 29 hours) Limitations -*research uses small samples/case studies* Siffre’s study, case study of himself, may not represent of wider population, limits generalisability as not everyone’s circadian rhythms are the same. using same person factors prevent general conclusions (Siffre observed his internal clock ticked more slowly at 60 than when younger. -*poor control* Siffre had a lamp on from when he woke up til he went to bed (He’d assumed artificial lighting had no effect on free running clock). But Czeisler et al. (1999) adjusted participants’ circadian rhythms from 22 to 28 hours using dim lighting. Using artificial light may be like taking a drug that resets the participants’ biological clocks. suggests that researchers may have ignored an important confounding variable in circadian rhythm research, reducing validity of findings -*individual differences* cycles can vary from 13 to 65 hours (Czeisler et al. 1999). Duffy (2001) found some people display natural preference for sleeping:rising early (‘larks’) whilst others prefer to sleep/rise late (‘owls’). also age differences in sleep/wake patterns. So findings from sleep/wake cycle studies may not be generalisable

Answer 70

-Hormones, like melatonin, *increase and decrease* as part of your circadian rhythms. -Melatonin is produced and released from the pineal gland, levels peak during the hours of darkness. -By activating synapses in brain, melatonin encourages sleep. -When dark, more melatonin is produced, and vice versa

Answer 71

-*Internal fluctuations* of body temperature regulated by your circadian rhythms. -one of the best indicators of the sleep wake cycle. It is lowest at about 4 am and highest at 6pm; varying by around two degrees from 36 degrees centigrade in morning to 38 degrees centigrade in evening. -Sleep occurs when the body temperature drops. -Temperature rises during last few hours of sleep causes people to feel alert in morning. Small drops in temperature can occur between 2 and 4 pm which can account for why people sometimes feel sleepy during this time.

Answer 72

-the warmer we are (internally), the better our cognitive performance. -Folkard et al (1977) found that children who had stories read to them at 3pm showed superior recall and comprehension after a week compared to children who heard the same stories at 9am. -Gupta (1991) found improved performance on IQ tests when participants were assessed at 7pm as opposed to 2pm and 9am.

Answer 73

-*internal body clocks* that regulate many of our biological rhythms, Eg the influence of the suprachiasmatic nucleus (SCN) on the sleep-wake cycle.

Answer 74

-*tiny bundle of nerve cells* located in the *hypothalamus* in each hemisphere of the brain. They are the *primary endogenous pacemakers* in mammals. -*contains neurons* that *fire with a 24-hour pattern* regardless of any biological or external influences -Even when eyes are shut the SCN *gets info on light from the optic nerve*. (Light can penetrate the eyelids and special photoreceptors in the eye transfer light signals to the SCN)

Answer 75

-another *endogenous pacemaker* that the SCN sends messages to -contains *light sensitive cells* -When *light* is sensed *melatonin* production is *inhibited* (so light level falls, melatonin production increases) -Melatonin increases drowsiness and creates biological conditions needed for sleep. This induces sleep by inhibiting brain mechanisms that promote the awake state.

Answer 76

-*external time giving cues*, (eg light) -they *set our body clock* through entrainment. -This is *synchronisation of body to environment* -This interaction is possible due to the optic nerve registering external cues such as light -Endogenous pacemakers interact with exogenous zeitgebers

Answer 77

-*Destroyed the SCN connections* in the brain of *30 chipmunks* who were then *returned to their natural habitat* and observed for *80 days* -The chipmunks *sleep-wake cycle disappeared*. by end of study a *significant proportion of them had been killed by predators* cause they were awake and vulnerable to attack when they should’ve been asleep. -shows how *important the SCN* is in *regulating the sleep wake cycle*

Answer 78

-*Destroyed the SCN connections* in the brain of *30 chipmunks* who were then *returned to their natural habitat* and observed for *80 days* -The chipmunks *sleep-wake cycle disappeared*. by end of study a *significant proportion of them had been killed by predators* cause they were awake and vulnerable to attack when they should’ve been asleep. -shows how *important the SCN* is in *regulating the sleep wake cycle*

Answer 79

-Created *'mutant' hamsters* who had a *20 hour sleep-wake* cycle. -*Transplanted the SCN cells* from the mutant hamsters into *brains of normal hamsters* (24 hour sleep-wake cycle). -The normal hamsters *following transplantation* ended up on a *20 hour sleep-wake* cycle. -shows the *role of the SCN* in *establishing and maintaining the sleep-wake* cycle.

Answer 80

-*light* can be *detected by skin receptor sites on the body* even when the same information is not received by the eyes. -*15 participants* were *woken* at various times and a *light pad shone on the back of their knees*. -researchers could *produce a deviation in the participants' usual sleep-wake cycles* (up to 3 hours in some cases) -This *suggests that light is a powerful exogenous zeitgeber* that influence our brain and body.

Answer 81

-*schedules* that are imposed on us *by society* and are *key influences on our sleep wake cycle* e.g. times to eat, times to go to bed. -Entrainment of the body following jet lag is quicker when people eat and sleep when the local culture do, rather than responding to your own body and feelings of hunger and fatigue. -In *infants* the *sleep/wake* cycle is initially *random* but by *6 weeks the circadian rhythms begin* and by 16 weeks most babies are entrained.

Answer 82

-*schedules* that are imposed on us *by society* and are *key influences on our sleep wake cycle* e.g. times to eat, times to go to bed. -Entrainment of the body following jet lag is quicker when people eat and sleep when the local culture do, rather than responding to your own body and feelings of hunger and fatigue. -In *infants* the *sleep/wake* cycle is initially *random* but by *6 weeks the circadian rhythms begin* and by 16 weeks most babies are entrained.

Biopsychology (paper 2) Flashcards

(106 cards)