Biopsych paper 2 Flashcards
What does the term hemispheric laterlisation mean?
the ideas that two halves of the brain are functionally different and carry out different functions
How is language lateralised?
left side of brain is fro language most people ,brocas area for left frontal lobae and wernickes area fro left temporal lobe
the RH can only produce smaller words such as ok and yes
suggesting that RH is synthesiser and LH is anyalser
How is movement cotrolled byt the two hemipsheres?
LH controls the right side of the body
Rh controls the left side of the body
How is vision divided between the two hemispheres?
Is is CONTRALATERAL and IPSILATERAL
so each eye light from LVF and RVF
LVF of both of the eyes are connected to the RH and the RVF of both of the eyes is connected to the LH
what does this allow?
visual depth and perception
How is auditary area controlled by the hemispheres?
similiar arrangment as vision
What are split brain patients?
split brain patients are patient who have had tehir corpus callosum cut that connects the two hemispheres, to reduce their epileptic seizures
What was the purpose of sperries research?
to see how the two seperate hemispheres deal with speech and vision
What did sperry do in his research?
he had 11 split brain patients, who he had projected an image to their RVF processed by their LH and different image to their LVF procssed by their RH
because the connectino between the two hemipsheres are cut, the info from each hemisphere cannot be conveyed to one another which would usually give a complete picture
What is one strength of HL theory?
research shows that in connected brain the two hemispheres process tasks differently.
this was shows by FINK who used PET scans to identify which area of the brain were active during a visual prossecing task
Evidience showed that those who were told to look at a global elemt of an image a whole forest the RH was active but when required to focus on a detail the LH tended to dominate
What is one limiation linked to ONE BRAIN?
idea that Lh analyser and RH is synthesiser is wrong.
The idea that the two hemispheres have different functions but that idead that people may have a dimonant side of the brain creating a different personality is wrong.
Evideince comes from a researcher who looked at brain cans of 1000 people aged 7 to 29 yrs and found that there certain hmeispheres of brain was used for certain tasks but no dominant side.
What is one strenght of split brain rsearch?
One strength of slipt brain rsearch is research support
Evidience comes from a researcher who had shown split brain patients actually perform better than controls on a certain task such as identifying the odd one out out of an array of similiar objects. This is because in a connected brain the LH better cogntitive strategies are watered down by the inferiors RH
What is one limitation of split brain research?
Due to its generalisation issues it hard to estabalish a causal relationships . This is is because sperry had compared split brain patients to a neurotypical control group. But none of these people had epileptic siezures WHICH ACTS AS A CONFOUNDING VARIABLE, because any differneces between the patients could have been because of epilepsy rather than split brain. SO actually the different cognitve abilites fro split brain patients may have been due to their epilepsy.
What is the FMRI technique?
works by detecting blood oxgyen concentration in brain in response to neural activity in specific areas of the brain
this is because when a brains area is more activce it consumes more oxgyen so it there is an incrased demandso more blood flow
What type of image do FMRI produce?
3D image showing which parts of the brain are most active
What does an electrocephalogram measure?
it measures electrical activity in brain electrodes using a skull cap
what is produced from this?
prewsent brainwaves that are generated from multiple neurons.
These are often used to detect nay aryhtmic forms of activity suhc as brain tumour or epliepsy as they can show a deviation from the normal activity in the brain
What are ERP?
contains neural responses in relation to a specific activity suhc as sensory or cognitive.
all data from EEG is extranoutated/filtered out levcaing only brain activity in response to a specific stimuli
Can show which areas of the brain is triggered by which events
cognitive or perception
What does a post mortem examination involve?
involves the analysis of a dead brain , those who are chosen usually have a rare disorder or a deficit i their cognitive processes.
areas of the brain damage can show the cause of the disorder they expereince
this can also involve comparing it to a neurotypical brain
strengths of fmri?
npo radiuation so less invasive procedure and pain free
high spatial resolution os can clearly see how brain activity is localised.
2 limitation of FMRI?
expensive and has allow temporal resolution because there is a 5 second time lag behing image oi=n screen and initial firing of neuronal activity- so it doesnrt present true moment to moment brain activity
stregnth of EEG?
usefuyl for studying stages involving sleep stages and diagnosiing certian sleepo disorders or iussues with the brain as it allows the brain waves patterns of a neutotyocial braiun to be compared with a brain with deficicts
High temporal resolution so more true moment to moment brain activity
limiation of EEg?
is that it gives an avergae of all neuronal actovty rather thana spefiic spot in the brain
so it doesnt allow researcher to distiguihs between actvitvites orginating in different but adjacent locations
strenght of using ERP?
much more specfity of neuronal actovyt
and becuase the ERP data is derived from EEg data is also has a high temporal resolution
meaning it can be used for measuring cognitive functions such as alloaction of maintencxe of working memory model and localise them to areas
What are 2 limitation of using ERP?
lack od stnadradisation of methods between different researchers, making it difficult to confirm findings.
any background noise must be removed to estabalish specific areas of the brain in repsone to specific stimuli
What is one strength of post mortem examinations?
it has real world applications, such as BROCAS area being discovered and the link between language and areas of the brain
What are 2 limitations of using post moretm examination?
causation is an issues with this (as correlation between one area of the dmaaged brain does not mean that THAT would have caused it)
ETHICAL ISSUE of informed consent is present because participant may not be able to provide concent before death, but has lead to many discoveries about the brain.
Define biological rhythms?
and give two exmaples?
distinct patterns of chnages in the body that confrom to cyclical time periods and are influnced by internal body clocks (endogenous pacemakers) and external influneces (exogenous zietgbers)
exampls are ultradian and infradian rhythms
What is the biological rhythms governed by?
governed by internal body clocks ushc as the exogenous pacemaker and external influence such as the exogenous zeitgbers
Explain what ultradian rhyms are?
rhytms that occru many times during the day
Explain what infradian rhyms are?
rhytms that take longer than a day to complete
Describe the sleep wake cycle?
the sleep wake cycle is a biological rhythm that is governed by internal body clock (endogenous pacemaker) the SCN.
The SCN recieves light from above the optic chiasm and LIGHT which is an exogenous zeitgeber can reset the SCN.
What does sieffres cave study show about our sleep/wake cycle and how they are governed by internal and external influences? PROCEDURE ONLY?
sieff showed how our SCN is goverened/controlled by external factors such as light. This is because he spent 2 months in cave deprived of light and sound and resurfaced in mid spetmeber htinking it to be mid august
What did his study show and what were the findings?
it was shown that his free running biological rhythm settled down to one that was just under the usual 24 hrs and continued to fall asleep and wake up at regular times everyday.
Describe one other research eveidience?
partipinat spent 4 weeks ina bunker deprived of natural light
What were the findings?
all bt one of the participiants sleep wake cycel exteneded to 29 hrs and a cricadian rhythm of 24 hrs
What do both of these studies show?
Both studies show that the natural sleep wake cycle maybe slightly longer than 24 hrs but is entrained by exogenous zietgbers associated with the meal times and daylight hours of a 24hr day.
What are 2 strenghs and limiation of research into circadian rhtyms?
shift wirk,medical treatment and individual differences
shift work
one strength of rsearch into CR is that it has provided an undertsnading of consequences when they are disrupted.
An example of this is when nigth shift workers experice a reducced concentration of about 6 in the morning meaning mistakes are more likely . Also it has lead to finding that it can have a porr imapct on our health such as a higher risk of devekoping COHD.
Therefore this is a strength because it shows how sleep wake cycle can affect our productivity in the economy.
why is medical treatment a strength?
abother strength is that research has been used to improve the effectiveness of medical treatment/drugs. This is because circadian rthyms coordinate many processes withing the body such as heart rate and digestion, which can rise and fall during the nigth or daytime.. This has lead to the development of chronotherpaueteutics- which is personal treatment accrodidng the bodys biological clock.
For example taking aspiring to prevent heart attacks is most effective to take last things at night, so it reduces the risk of a heart attack in the morning (because they mostly occru in the morning so taking aspirin in the night helps to thin the blood over night.
Therefore this shows that rsearch into SWC can help in medical treatment.
What is one limitation?
One limitation of research into SWC is that there are individual differences.
This is because the studies from sieff and bunker one are based off very small number of participiants and actaully vary from person to person.
Evidience comes from a rsearcher who found a individual differences in sleep wake cycles varying from 13 to 65 hours, and some people have a natural preferenace fro going to bed early and waking up early or opposite people.
this means that the rsearch data to discuss anything more than averages is meaningless.
Define infradian rythms?
is a biological rythm that has a frequency of less than one cycle every 24hrexamples (becasue it takes a month to complete)
Describe the menstrual cycle as being an infradian rhthym?
the menstrucal cycke is an example of an infradian rhthym because it frequynecy is less than one cycle in 24 hours as it takes 28 to 30 days to complete.
it is governed by hormones levels and regulates ovulation. as when oestrogen peaks then ovulation occurs , then only will the second last phase start which is the luteal phase where progestrone levels increase to make the lining of the womb thicker in prep for pregnancy
Describe the study that shows the synchronisation of the menstrual cycle?
the mensural cycle is governed by endogenous system but can be influenced by external factors such as cycle of other women by influence of pheromones.
This was shown by researcher who gathered 29 women with a irregular period cycle.
Samples of pheromones were gathered from 9 different women eahc on a different stage of their menstrual cycle. worn for 8hr in armpit
rubbed on upper lip and rubbed the cotton pad of the women on her first day of her menstrual cycle and so on until her last day
68% 18 women had experienced cycle changes that had brought them closer to their odour donour, showing how infradian rhythm can be influenced by exogenous zeitgebers.
What is SAD AND DESCRIBE IT ?
SAD is seasonal affective disorder w3hidh shares some of the sympotms of depression and low mood and low energy.
Often tirggered in the winter months as number of daylight hours become shorter is subject toa yearly cyclle.
the hormone MELATONIN maybe responsible for this as the pineal gland releases melatonin until dawn when an increase in light is detected from the optic chiasm/ SCN.
during winter due to lack of light the secretion continues so it has a knock on effect on the production of seratonin in the brain - whichcauses depression.
What is one strength of the mentrual synthcrony research?
one +is that it can be explained by evolutionary basis through ntaural selection. This is becasue our ascnestors may have synchrnised menstrual cycles to become pregnat at the same time so if mother were lost during or after childbirth then they wouls still be able to surviweve and grow due to the access of care through the other mothers increasing chnaces of survival. There fore synchrnising mentraul cycle maybe an adaptive stratgey.
What is one limiation of infradian rhythm rseaerch in rlation to mehtodocligal issues?
This is becasuse there are many mehtodoglical problems. This is bvecause there are many other factors which can impact the mentrual cycle such as stress diet or exercise which may act as CONFOUNDING VARIBALES, which means that the synchriniastion of menstrual cycle could be because of just chance. So THIS IS ALSO WHY OTHER HAVE FAILED TO REPLICATE THE FINDINGS.
What is an ultradian rhythm?
a biologicaql ryhtm that ahs a fREQ of more then one cycel in 24hrs such as stagesof sleep
How are sleep stages measured by? and how long does each cycle last?
EEG and lasts 90 minutes (one whole cycle)
what are stage 1/2 of sleep ?
light sleep person easily woken
brain waves have high FReQ and short amplitude (alpha waves) stages 2 may have sleep spindles.
What is stage 3/4 of sleep?
DEEP SLEEP OR SWS delta waves of low FREQ and high apmlitude, difficult to wake up someone
What is stage 5 called and describe the brain activity?
REM sleep / body aslpee but brain resembvles acvtiovyt of being awake. produces theta waves and eye rapudely moves
drams are often experinced
What is one strength of research into ultradian rhythms?
One+of rseerahc into ultradian rhythm is improved undertsnading of age related changes in sleep.
This is because slow wave sleep reduced with age, and because the growth hormone is produced during this time , there is a deficency of this. This can then caus the issues of old age such as reduced alertness. but in order to increase this SWS, meditation or relaxation techniques can be used. This means that research has practical value as it can help older people and the age relkated chnages.
What is one limitation of ultradian rhythms?
one - is that tehgre are individual differences in between partipinats in terms of the duration of each stage of sleep , particularly in stages 3 and 4, and are usually biologically determined., therefore this make it difficult to describe normal sleep.
What is one example of a endogenous pacemaker?
SCN superchiasmatic nucleus
describe what the SCN is and what does it do its role in the sleep wake cycle?
SCN is a tiny bundles of nerves located in the hypothalamus in each hemisphere of the brain.
it maintains the circadian ryhtms.
it lies right above optic chiasm which is where the nerve fibres of the eye cross to the left and right visual field.
This helps its recieve light from even when our eyes are closed to help adjust to changing patterns of daylight.
What did animal studies and the SCN show?
de corutesy et al destroyed the SCN connecttions in brains of 30chipmunks and were returned to their natural habitat for 80 days.
it was found that most of them had been killed by predators because they were awake when meant to be sleeping and vulnerable to attck when they should have been asleep.
foetal tissue of mutant bred hamster s were tranferred and defaulted to 20hrs
How are the pineal gland melatonin and SCN linked?
The SCN passes on infromation about length of day and light to the pineal gland. This is responsible in the prodcution of melatonin inhibiting wakefullness and inducing sleepyness
What is one limitation of ENDG of other clocks being more powerful?
one limiation of the SCN is that it can obscure other body clocks.
This is because research shows that there are circadian rhytms in many organs and cells which are called periphreal oscilators and are found in the lungs pancreas and liver.
although they are influenced by the SCN they act indenpandtly, as when a researcher how feeding patterns in mice could later their circadian rhytm of cells in the liver by upto 12 hrs, while leaving the SCN unaffected, suggesting there other influences on the sleep wake cyle.
What is another limitation of the SCN being a interactionist system?
another limitation of ENDG pacemakers is that they cant be studied in isolation, total isolation studies are pretty rare and in sifferes cave study the use of an articial light could have reset his biological clock every time he turned it on, and in real life ENDG pacemaker and EXG zeitgber interact so it it makes little sense to seperate the two for research.
so it make the studies less valid.
Define exogenous zeitgber?
external factors in the envrioment that reset our bioogical clocks through entraining and are light and social cues.
Why is light a external cue that can affect the SCN and our sleep wake cycle?
can reset the SCN and can control functions such as hormone secrettion and blood circulation.
What did MURPHY find in his study into light affecting our sleep wake cycle?
light can be detected by our recpetor sites on our skin even when not recieved by eyes.
what did he do?
he shone light at the back of knees in 15 particpiaints and produced a cyce deviation of 3 hours, suggestin light is a powerful EXGZ and does need to rely on eyes to influence the brain
How does social cues affect the SCN?
social cues can include meal times and babies are usually pretty random, but at 16 weeks the babies circadian rhythms become entrained by social cues such as meal times and bedtimes.
to beat jet lag it is found to adapt to local times for eating and sleeping rather than own feeligns of hunger and fatigue to entrain the circadian rhytmand beat jet lag.
What is one limitation of EXG zeitgber, in different enviroments?
one limitation is that EXG dont have the same affect in all enviroments. This is becasue people who live in places where there is very little darkness in summer and very little light in winter usualy have a similiar sleep apttern all year around. despite spending six months in total darknes, such aas those who live in artic circle. suggesting that the sleep wake cycle is controlled by endogenous pacemakers that can overdie envriomental changes in light.
Whta is another limitation of EXG relating to a blind man?
One limitation of eXG is case study eveidince shows that meal times and social cues arent just enought to entrian the sleep wake cycle and that ENDG has a strogner influence.
a young blind man from birth had a abnormal circadian rhythm of 24.9hrs, despite regular meal times it couldnt be adjusted.
