biopsychology Flashcards

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1
Q

describe fight or flight

A

the endocrine system and ANS often work together like in stressful events.
a stressor is perceived so the hypothalamus triggers activity in sympathetic branch of the ANS.
ANS changes from normal resting state (parasympathetic) to physiologically aroused sympathetic state. adrenaline is released from the adrenal medulla into the bloddstream.
this triggers physiological changes like increased heart rate to create physiological arousal needs for fight or flight. its an automatic instant response. once the threat passes then parasympathetic returns body to resting state.
sympathetic - increases heart rate and breathing, dilates pupils, inhibits digestion and saliva production and contracts rectum
parasympathetic - decreases heart rate and breathing rate, constricts pupils, stimulates digestion and saliva production and relaxes rectum.

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2
Q

describe the endocrine system.

A

the endocrine system works alongside the nervous system to control vital functions. its slower than the nervous system.
glands in the body like the thyroid produce hormones that are secreted into the bloodstream and affect any cells in the body with a receptor for that hormone.
most hormones affect cells in several organs or through the whole body e.g. the thyroid gland produces thyroxine that increases heart rate, metabolic rate and affects growth rates.
the major endocrine gland is pituitary gland, often called the ‘master’ gland as its controls the release of hormones from all endocrine glands in the body.
theres the pituitary, thyroid, parathyroid, adrenals, pancreas, ovaries and testes.

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3
Q

describe the nervous system.

A

the nervous system has two main functions - to collect, process and repsond to info in the environment and to coordinate the working of different organs and cells in the body.
thers 2 subsystems - central nervous system (CNS) and peripheral nervous sytem (PNS).
the CNS is the brain and spinal cord. the brain is the centre of all conscious awareness. the outer layer (cerebral cortex) is highly developed in humans and distinguisges us from animals. the brain has 2 hempishered and the spinal cord is responsible for reflex actions and passes info to and from the brain and connects nerves to the PNS.
the PNS transmits mesages via neurons to and from the CNS. its sub-divided into the autonomic nervous system (ANS) and the somatic nervous system (SNS). the ANS governs vital functions like breathing (involuntary) and SNS controls muscle movement and receives info from sensory receptors (voluntary).

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4
Q

how does synaptic transmission work

A

signals transmitted electrically down a neuron but chemically between them - neurotransmitters pass from the presynaptic from synaptic vesicles, across the synapse. it gets received by receptors on the postsynaptic neuron. chemical turns back to electric and transmission repeats.
each neurotransmitter ha sits own special function and has its own specific molecular structure that fits perfectly into post-synaptic receptor site, like a lock and key.

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5
Q

what is inhibitory, excitation and summation?

A

excitation is when a neurotransmitter increases the positive charge of a presynaptic neuron. it increases the likelihood of a neuron firing and passing on an electrical impulse.
inhibitory is when a neurotransmitter increases the negative charge of the postsynaptic neuron which decreases the likelihood a neuron fires and passes on electrical impulses.
neurotransmitters are either excitatory or inhibitory. e.g. serotonin is a neurotransmitter which causes inhibition and adrenaline (neurotransmitter and hormone) causes excitation.
summation is the process of whether a postsynaptic neuron will fire or not.
excitatory and inhibitory influences get summed - if the net effect on postsynaptic is inhibitory then its less likely to fire. if the net effect is excitatory then its more likely to fire - the inside of a postsynaptic neuron gets positively charged and the electrical impulse travels down a neuron.
therefore the action potential of postsynaptic is only triggered if sum of excitatory and inhibitory signals at any time reaches the threshold.

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6
Q

what is a neurotransmitter?

A

neurotransmitters are chemicals that diffuse across synapses to the next neuron in the chain.
the neurotransmitter crosses the synapse and is taken up by postsynaptic neuron. chemical message get converted back to an electrical impulse and process of transmission repeats in this neuron.

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7
Q

explain how sensory relay and motor neurons function.

A

the function of sensory neurons is to send info from the senses to the brain, e.g. if someones digging and hits a rock. the sensory neurons in their hand and arm feel this and send the info to the brain.
relay neurons decide what to do in this situation.
motor neurons control movement by passing info from the brain to the muscles. the brain would pass on the info to stop diggning to the persons arm.

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8
Q

explain all the parts of a neuron.

A

there is the cell body/ soma.
the nucleus contains genetic material of the cell.
dendrites carry nerve impulses from neighbouring neurons to the cell body.
node of ranvier enhances the electrical signals that travel down the axon.
axon carries impulses from cell body down the length of the neuron.
myelin sheath is fatty layer that protects the axon and speeds up electrical transmissions of impulse.
axon terminals communicate with the next neuron in the chin across the gap - synapse.

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9
Q

describe plasticity

A

plasticity is the brains tendency to change/ adapt as a result of experience and new leanring. in infancy the brain has rapid growth of synaptic connections - peaking at 15000 at 2-3 years old, double the amount thats in an adult brain. as we age connections that are rarely used get deleted, but some are also strengthened - synaptic pruning.
new research shows any time in life neural connections can change/ form due to learning/ experience.

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10
Q

describe plasticity - research from maguire, draganski and mechelli

A

maguire 2000 studied london taxi drivers brains and found more grey matter in the posterior hippocampus than in control gorup. this is the part of the brain linked to spatial and navigational skills. when they were training they took a test called ‘the knowledge’ that tests recall of streets and routes. the longer they were in the job, the more structural differences they had (positive correlation).
draganski 2006 imaged brains of medical students 3 months before and after their final exams. learning induced changes in posterior hippocamous and parietal cortex.
mechelli 2004 found larger parietal cortex in bilinguals than in matched monolinguals.

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11
Q

describe brain recovery after trauma

A

theres functional recovery which is a form of plasticity. after physical injury/ trauma, unaffected areas of the brain adapt and compensate for the damaged areas. this process can occur quickly after trauma (spontaneous recovery) then slow down after several weeks or months.
after this the patient may need rehabilitative therapy. the brain is able to rewire/ reorganise by forming new synaptic connections near that area of damage.
secondary neural pathways are activated so function continues (Doidge 2007). this process is supported by 3 things:
axonal sprouting - growth of new nerve endings that connect with undamaged nerve cells to form new paths.
reformation of blood vessels.
recruitment of homologous areas - on opposite sides of the brain to perform specific tasks e.g. if brocas got damaged on the left, the right side equivalent carries out function and then it can shift back to left.

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12
Q

what are 3 strengths of plasticity and brain recovery?

A

one strength is understanding processes in plasticity has contributed to the field of neurohabilitation. after brain injury, spontaneous recovery slows down after a few weeks so physical therapy is needed to maintain improvements (e.g. therapy/electrical stimulation of brain to counter cognitive or motor deficits). shows brain can ‘fix’ itself to a point but needs further intervention to be successful.
another strength is negative plasticity. brains ability to rewire itself can have maladaptive behavioural consequence. prolonged drug use can lead to poorer cognitive functioning and increased risk of dementia later in life (Medina). 60-80% amputees report phantom limb syndrome - continued experience of sensations in missing limb. sensations normally unpleasant, painful and its thought to be due to cortical reorganisation in the somatasensory cortex that occurs from limb loss (ramachandran and hirstein).
last strength is age and plasticity. functional plasticity reduces with age. brain more likely to reorganise in childhood as we are constantly adapting to new experiences or learning. but bezzola 2012 showed 40 hours of golf training produced changes in neural representation of movement in pts 40-60 years. used fMRI and observed reduced motor cortex activity in novice group compared to control. suggests more efficient neural representations after training. shows neural plasticity does continue through lifespan.

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13
Q

describe fMRI

A

fMRI is functional magnetic resonance imaging. it detects changes in blood oxygenation that occurs due to neural activity in specific areas.
active areas consume more oxygen so to meet this increased demand, blood flow is directed to the active areas - haemodynamic response.
3-d images show which brain areas are active in particular mental processes.

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14
Q

what is a strength of fMRI

A

a strength is it doesnt rely on using radiation like PET scans. its risk free, non invasive and easy to use. the images have a high resolution to millimetres so gives a clear picture of localisation.

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15
Q

what is a weakness of fMRI

A

a weakness is its expensive compared to other techniques and only gives a clear image if the person is still. it has poor temporal resolution with a 5 second lag between the image and the actual brain firing. it only measures blood flow so cant see individual neuron activity which means its difficult to see what kind of brain activity is represented.

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16
Q

describe EEG

A

EEG is electroencephalogram and it measures electrical activity in the brain using electrodes fixed to the individuals scalp with a skull cap.
the scan represents brainwave patterns from the actions of millions of neurons so gives an overral account of brain activity.
we can use it as a diagnostic tool for unusual arrhythmic patterns as they can indicate neurological abnormalities like epilepsy, tumours or sleep disorders.

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17
Q

what is a strength of EEG

A

a strength is its invaluable in diagnosing conditions like epilepsy. its also contributed to understanding of sleep stages. it also has a high temporal resolution with one millisecond or less.

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18
Q

what is a weakness of EEG

A

a weakness is the generalised nature of the info received. cant pinpoint the exact source of neural activity and cant distinguish between activities originating in different but adjacent loactions.

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19
Q

describe ERPs

A

ERPs are event related potentials. EEGs are overly general and in there data theres all the neural responses in specific sensory cognitive and motor events.
to isolate these responses we use statistical averaging technique to filter out extraneous brain activity only leaving responses related to a specific task - we get left with an ERP.
the types of brainwaves are triggered by a particular event.

20
Q

what is a strength of ERPs

A

a strength is they bring more specificity to EEG measurements. it has excellent temporal resolution. it identifies many types of ERP and describes their precise role in cognitive functioning.

21
Q

what is a weakness of ERPs

A

a weakness is the lack of standardisation in methodology between different resarch studies so its difficult to confirm findings. for pure data extraneous noise has to be eliminated which isnt easy.

22
Q

describe post mortem examinations

A

post mortem examinations (PME) is analysing a persons brain after their death. in psychological research we normally look at individuals with rare disorders or unsual deificts in their mental processes.
we examine areas of damage to establish causes of afflcition the person suffered. it can involve comparisons to neurotypical brains to see the extent of the difference.

23
Q

what is a strength of post mortem examinations

A

a strength is that post mortem evidence is vital in showing a foundation for early understanding of key processes in the brain. Broca and wernicke both relied on PME to establish links between language, brain and behaviour before neuroimaging was invented. it can improve medical knowledge or generate hypothesis for further study.

24
Q

what is a weakness of post mortem examinations

A

a weakness is causation. observed damage may not be linked to deficits but to unrelated trauma or decay. also ethical issues - can we get consent from the patient before death. the patient may not be able to give informed consent e.g. HM couldnt form memories so couldnt give consent but they still did a PME.

25
Q

explain localisation of function

A

localisation is the theory that different areas of the brain are responsible for different behaviours, processes and actions. holistic is the idea all parts of the brain are involved in processing thoughts and actions.
the brain has 2 halves - the left and right hemisphere. lateralisation is where a particular hemisphere controls specific physical and physiological functions. the right hemisphere controls left side of the body and vice versa. they are all surrounded by the cerebral cortex.

26
Q

explain localisation of function - the 4 lobes

A

there are 4 lobes - frontal, parietal, occipital and temporal. they all have different functions.
the back of the FL is motor area for voluntary moments and damage to it means a loss of control in fine movements.
front of PL is somatosensory area for sensory info from the skin (heat, touch and pressure).
the OL has a visual area. the right visual field goes to the left visual cortex and vice versa. damage to left hemisphere equals bindness in rigth visual field of both eyes.
the TL has auditory area for speech based info and damage can mean hearing loss.
damage to a specific area like wernickes can affect the ability to comprehend language.

27
Q

describe the 2 language areas in the brain

A

language is restricted to the left hemisphere.
Paul broca found an area in the left FL thats responsible for speech production. damage to brocas area cause brocas aphasia - slow laborious lack of fluency like in ‘tan’ where he could only say ‘tan’.
karl Wernicke was finding patients with no problems producing language but with severe difficulties in understanding it so the speech they produced was fluent but meaningless. found wernickes area was responsible for language comprehension so damage results in wernickes aphasia so they produce nonsense words (neologisms) in their speech.

28
Q

what are 3 strengths of localisation

A

one strength is theres lots of brain scan evidence showing many neurological functions are localised, primarily language and memory. Petersen 1988 used brain scans to show wernickes active in listening tasks and brocas was active in reading tasks. this shows the areas have different functions. tulvings LTM 1994 showed semantic and episodic are in different parts of the prefrontal cortex. theres now lots of sophisticated and objective methods to show localisation with sound scientific evidence.
another strength is neurological evidence like Walter freeman’s lobotomy that involved severing connections in frontal lobe to control aggressive behaviour. Dougherty 2002 had 44 OCD patients whoo went through ‘cingulotomy’. after 32 weeks 1/3 had successful responses and 14% had partial. success shows symptoms or behaviours of severe mental disorders are localised.
the last strength is case study evidence. unique cases of neurological damage support localisation like phineas gage.

29
Q

describe split brain research - method

A

hempisheric lateralisation is the idea that the 2 hempispheres are functionally different so certain mental processes are controlled in one hmepisphere than the other (e.g. language in left).
sperry did ‘split brain research’ in 1968 on a group of people whod all had an operation ‘commissurotomy’ (corpus callosum cut to seperate hempisheres and control frequent and severe epileptic seizures. communication between 2 hemispheres was stopped so they could see how much the hemispheres are specialised.
he used a general procedure where words or images were prijected to the right visual field (RVF). in a normal brain the corpus callosum shares info between both hempisheres so they get a full visual picture.
but in sperrys study if you only present info to one hemisphere it means the patient couldnt convey info between the hemispheres.

30
Q

describe split brain research - findings

A

he found that when the picture was shown to the RVF the pt could describe what they saw. if it was shown to the LVF they couldnt and said there was nothing there.
language is processed by left hemisphere. we cant describe it if its shown to the LVF as theres no language centre in the right hemisphere. if shown the object in the LVF they could select the matching object from a bag with their left hand. they couldnt verbally identify object but they could understand what the object was with the right hemisphere.
if 2 words were shown simultaneously, one on either side of the visual field (e.g. a key on the LVF and ring on RVF) the pt could select the key with their left and and say the word ring. the right hemisphere was dominant in drawing tasks and also recognising faces. they could match face from a series of other faces if the picture was processed by the right hemisphere (LVF) they could select the correct one but if it was presented to the left hemisphere it got ignored.
if a picture with two halves was presented (one half to each hemisphere) the left was dominant in verbal description but right was better at selecting the matching picture.

31
Q

what are 2 strengths of split brain research

A

one strength is its demonstrated in lateralised brain functions. sperrys work showed the LH was more analytic and did better at verbal tasks but the right was better at spatial and music tasks. the RH produces rudimentary words and phrases but contributes emotional and holistic content to language. LH is an allayer and RH is a synthesiser. it gives key understanding into brain processes.
another strength is its methodology as it used highly specialised and standardised procedures. showing visual info to one hemisphere at a time and showing it for 1/10 of a second allowed sperry to vary aspects of procedure and meant only 1 hemisphere received info at a time, this means its a useful and well controlled procedure.

32
Q

what is 1 weakness of split brain research?

A

a weakness is we cant generalise the findings. split brain participants are such an unsual sample of people. only 11 people took part in all variations of the basic procedure, all with epilectic seizures which may have caused unique changes in the brain that may have influenced the findings. also, from the surgical procedure some had more of a disconnection of the 2 hempispheres than other had. also control group was 11 people without seizures which may not have been suitable.

33
Q

describe circadian rhythms

A

biological rhythm is a distinct pattern of change in body activity that conforms to cyclical time periods.
its influenced by internal body clocks (endogenous pacemakers) and external environmental changes (Exogenous zeitgebers).
some occur many times in a day (infradian) or even longer than that (circannual).
circadian is around 24 hours (sleep wake and core body temperature).

34
Q

describe circadian rhythms

A

circadian is around 24 hours (sleep wake and core body temperature).
the sleep wake cycle means you feel drowsy at night and alert in the day which shows the effect of daylight (an exogenous zeitgebers.
several studies tried to see if we dont know if its day or night, will we still sleep and wale at regular times.

35
Q

describe circadian rhythms - siffre

A

in siffres cave study he seperately spent 2 and 6 months in caves. he was deprived of exposure to natural light and sound but had food and drink.
after 2 months in the cave he came out in september 1962 thinking it was mid august.
in this study his biological rhythm settled to around 25 hours but he still slept and woke on a regular schedule.
aschoff and wever, and siffre both show how sleep/ wake cycle may be longer than 244 hours but its entrained by exogenous zeitgebers linked with the 24 hour day, like daylight hours.

36
Q

describe circadian rhythms - aschoff and wever

A

aschoff and wever 1976 got a group of pt to spend 4 weeks in a WW2 bunker with no natural light. all but 1 pt (who had 29 hours) had a circadian rhythm of 24-25 hours.
aschoff and wever, and siffre both show how sleep/ wake cycle may be longer than 244 hours but its entrained by exogenous zeitgebers linked with the 24 hour day, like daylight hours.

37
Q

describe circadian rhythms - folkard

A

but we shouldnt overestimate influence of environmental cues on the internal biological clock.
folkard 1985 studied 12 people in a dark cave for 3 weeks going to bed when teh clock said 11.45pm and they woke when the clock said 7.45am.
over the study the researchers sped the clock to make the day 22 hours long. only 1 pt adjusted to the new hours.
this suggests the existence of a strong free-running circadian rhythm, which cant be easily overriden by changes in the external environment.

38
Q

what are 2 strengths of circadian rhythms

A

one strength is its practical application to shift work. knowledge of circadian rhythms have given us a better understanding of bad consequences from disruption (desynchronisation). night workers on shift have reduced concentration around 6am so they have more mistakes or accidents (Boivin). theres also a link between shift work and poor health - 3x more likely to get heart disease (Knutson) which could be due to the stress of a different sleep/ wake cycle. research may have economic implications into managing worker productivity.
another strength is practical applications to drug treatments. circadian rhythm, coordinate processes like heart rate etc. effect the action of drugs on the body like how well they are absorbed and distributed. research has shown peak times in day or night when drugs are most effective. its helped with guidelines for meds like anti epileptic drugs.

39
Q

what is 1 weaknessof circadian rhythms

A

a weakness is it uses case studies or small samples e.g. siffre is only one person. it snot representative of the wider population so means we cant make meaningful generalisations. siffre did another cave study in 1999 aged 60 and his internal clock was slower than when he was younger. even using the same person across time its still hard to draw conclusions.

40
Q

describe infradian rhythms - menstrual cycle

A

menstrual cycle is an example of an infradian cycle (less than 1 cycle in 24 hours) thats controlled by monthly changes in hormone levels that regulate ovulation.
the time between the 1st day of the period to the day before the next period has an average of 28 days, but normal is 24-35 days.
rising oestrogen causes the release of an egg (ovulation) and after ovulation progesterone thickens the womb lining which stays if you fall pregnant or falls away if you dont.
the menstrual cycyle is endogenous but can be influenced by exogenous things like the cycles of others.
stern and McClintock 1998 showed that pheromones can influence menstrual cycyle. they used 29 women with irregular periods.
they took samples of pheromones from 9 of the women at different stages of their cycyle. they held a cotton pad in their armpit for at least 8 hours. the pads were then frozen to be rubbed on the upper lip of the other 20 women.
on the first day of their cycyle they were given a day 1 pad and so on.
68% of women had changes to their cycle that made them closer to the pheromone donor.

41
Q

describe infradian rhythms - seasonal affective disorder

A

seasonal affective disorder (SAD) is another infradian example. its a depressive disorder with a seasonal pattern.
its characterised by low mood and a lack of activity/ interest in life triggered by the winter months (winter blues) when the daylight hours get shorter.
its a circannual rhythm as its a yearly cycle, it can also be ciracdian as SAD cab be from a disruption of sleep/ wake cycle.
melatonin is involved in SAD. at night the pineal gland secretes melatonin till dawn when it becomes light. in winter this is a longer process as theres less light so it can reduce production of serotonin.

42
Q

describe ultradian rhythms - sleep cycle

A

in ultradian cycles (more than 1 in 24 hours) is the 5 stages of sleep.
stage 1-2 is light sleep with slower rhytmic alpha waves. as sleep deepens they become slower (theta waves).
stage 3-4 has delta waves that are slower with a greater amplitude. its deep/ slow wave sleep.
stage 5 is REM sleep where the body is paralysed and brain activity speeds up like your awake. REM leads to rapid movements like fast jerky movements under the eyelids of the eyes. theres a high link to dreaming.

43
Q

what is 1 strength of infradian and ultradian rhythms

A

the strength is evidence to support sleep stages. dement and kleithman 1957 monitored 9 adults sleep patterns in a sleep lab. brainwave activity was recorded on EEG and controlled for effects of caffeine and alcohol. REM was hughly corrected with dreams and brain activity varied according to vividness of a dream. they woke with accurate recall of their dreams and replications get similar results. this shows the importance of REM.

44
Q

what are 2 weaknesses of infradian and ultradian rhythms

A

one weakness is the menstrual cycle, like what was observed in mcclintons study, is supposed to have evolutionary value. for our ancestors it may have been better to mentrsuate and fall pregnant at the same time as others so newborns could be cared for collectively so increases their chance of survival. the validity of this perspective was questioned by schank 2004 who said if too many females were in the same cycle there’d be competion for the highest quality males (higher fitness of offspring). this point of view argues avoiding synchrony is the best evolutionary strategy.
another weakness is the methodology in synchronisation studies. people argue mnay factors change menstrual cycle e.g. stress and diet change that act as confounding variables. pattern of synchrony in McClintock is by chance, it had a small sample and relies on self report. other studies (trevathan 1993) failed to find synchrony in samples.

45
Q

describe endogenous pacemakers

A

endogenous means internal. the suprachiasmatic nucleus (SCN) is a tiny bundle of nerve cells in the hypothalamus. primary endogenous pacemaker maintains circadian rhythms like sleep and wake cycle.
nerve fibres connected to the eye cross in an area called optic chiasm. the e.pacemaker receives info about light from this chiasm. it continues even with your eyes closed.
influence of SCN was demonstrated in studies with animals.
decoursey 2000 destroyed SCN connections in the brains of 30 chipmunks that got returned to their natural habitat and were observed for 80 days. their sleep/ wake cycle disappeared and a large number got killed by predators (they were awake and vulnerable).
ralph 1990 bred ‘mutant’ hamsters with 20 hour sleep/ wake cycles. SCN celss from foetal tissue of mutant hamsters transplanted into brains of normal hamsters. the cycles of the 2nd group changed to 20 hours. this emphases the role of SCN in sleep/ wake cycle.
SCN passes info on the day length and light it receives to pineal gland. in the night the pineal gland increases melatonin production so induces sleep and gets inhibited when awake. it could also be a factor in SAD.

46
Q

describe exogenous zeitgebers

A

exogenous means external. we can reset our biological clock through ‘entrainment’. if we have no external cues the biological clock controlling sleep/ wake cycle keeps going in a cyclical pattern, so we need a mix of internal and external factor.
light is a key zeitgeber which can reset the bodys SCN so plays a role in maintaining sleep/ wake. it also indirectly influences processes that control functions like hormone secretion and blood circulation.
campbell and murphy 1998 showed light can be detected by skin receptors even if eyes arent getting the same info. 15 pts were woken at different times by shining light on the back of kness. this produced. deviatiion of upto 3 hours.
light is a powerful exogenous and we dont need to rely on eyes to influence the brain.
social cues can also effect it. infants arent on the same sleep/ wake cycle as the rest of the family. its random till 6 weeks when circadian rhythms start. by 16 weeks its normally entrained. parent schedules like an adult-determined meals and bedtimes normally are a key influence.
using local times for eating and sleeping is effective to entrain circadian rhythms and beat jet lag.

47
Q

what are 3 weaknesses of endogenous pacemakers and exogenous zeitgebers

A

one weakness is research showed multiple circadian rhythms in organs and cells called ‘peripheral oscillators’ in the adrenal gland, oesophagus, lungs, liver, pancreas, spleen, thymus and skin. these peripheral clocks are highly influenced by actions of SCN but they can act independently. damiola 2000 showed chanign feeding patterns in mice could alter circadian rhythm in liver cells by 12 hours with the SCN being unaffected. may be other complex influences on sleep/ wake other than SCN.
another weakness is ethics in the animal studies. decoursey exposed animals to huge harm and risk in their natural habitat. does what we learn justify the procedures involved? we also cant generalise animal findings to hmumans.
the last weakness is that the influence of exogenous may be overestimated. miles 1977 told the story of man blind from birth with a circadian rhythm of 24.9 hours. exposure to social cues didnt change sleep/ wake so needed sedatives at night and stimulants in the morning to keep pace with the 24 hour world. Studies of individuals who live in arctic regions where the sun doesnt set in the summer show normal sleep patterns even though they have prolonged exposure to light. both examples show exogenous may have little influence.