biopsychology Flashcards
localisation vs holistic theory - localisation of function in the brain
broca/wernicke; specific areas of brain assoc w partic physical/psychol funct, they arg for localisation of function
diff parts of brain performed diff tasks/involv diff parts of body
if cert area beco damaged thru illness/injury then funct assoc w area also affected
b4 this scientists supp holistic view that all parts involv in processes of thought/action
hemispheres of the brain - localisation of function in the brain
main part of brain (cerebrum) divided into 2 symmetrical halves, left and right hemispheres
some of our phys/psychol funct controlled by partic hemisph, lateralisation
activ on left side controlled by right hemisph, visa versa
the motor, somatosensory, visual and auditory centres - localisation of function in the brain
cerebral cortex of both hemispheres subdivided in2 4 lobes of brain
lobe sep fr rest /assoc w diff funct
frontal lobe; motor area wh contr voluntary movem
parietal lobes; somatosensory area where sensory info fr skin rep
occipital lobe, visual area, ex. eye sends info fr right visual field to left visual cortex
temporal lobe; auditory area, analyses speech based info, damage may cause partial hearing loss
the language centres of the brain - localisation of function in the brain
lang restrict to left side of brain, broca’s area in left frontal lobe
damage = brocas aphasia and produces slow lacking fluency speech
wernickes area, left temporal lobe resp for lang underst
damage = wernickes aphasia and produces nonsense words as part of speech
evaluation - evidence fr neurosurgery; localisation of the brain
strength
damage to areas of brain linked to ment disorders
cingulogomy; isolating cingulate gyrus wh implicated in ocd
dougherty et al; rep on 44 peop w ocd who undergone cingulotomy
post surgery aft 32 weeks fou 30% met criteria for successf resp and 14% for partial resp
TF: success of proced sugg beh assoc w serious ment disorder may be localised
evaluation - evid fr brain scans; localisation of brain
strength
peterson et al; used brain scans and demost how wernickes area active dur listening task and brocas dur reading task
buckner/peterson; review LTM stud fou semantic/episodic memories reside in diff parts of prefrontal cortex
studies confirmed localised areas for everyday beh
TF: object meth for meas brain activ prov scientific evid that brain funct localised
evaluation - counterpoint to evid fr brain scans ; localisation of brain
limit
lashley; remov areas of cortex in rats that were learning route in maze and fou no area more import than oth area 4 rats ability to learn route
process of learning req every part of cortex than just confined to 1 area
TF: sugg higher cog proc ie. learning distrib in holistic way in brain
evaluation - lang localisation questioned ; localisation in brain
limit
lang x localised to broca/wernickes area
dick/tremblay; fou only 2% modern research. think lang complet control by broca /wernickes areas
fmri means neural proc in brain can be studied +re clearly
lang streams identif across cortex inclu brain regions in right hemisph/sub cortical regions
TF: sugg lang organised +re holistically in brain wh contradicts localisation theory
left and right hemispheres - hemispheric lateralisation/split brain research
for lang 2 main centres only in LH, broca’s areas left frontal lobe and wernickes area in left temporal lobe
so lang laterised, perf by 1 hemisphere and RH can only produce rudimentary words/phrases b contrib emot context
LH = analyser and RH = synthesiser
motor area; brain is cross wired, RH contr movem on left side body b LH contr movem on R
for vision b contralateral/ipsilateral so each eye receives light fr LVF/RVF
LVF of b eyes connected to RH/RVF b eyes connected to LH wh enables visual areas to compare slightly diff perspective fr each eye/aids death perception
sperrys research procedure - split brain research
spilt brain; severing connections b/w RH/LH, surgical proc 2 reduce epilepsy
SB res stud how hemisph funct when can’t communicate w each oth
proc; 11 peop w split brain op stud using set up where image presented to ppts RVF/image to LVF
in norm brain, corpus callosum immed share info b/w b hemisph b w split brain cx
sperrys research findings - split brain research
findings; when pic of obj shown to ppt RVF ppt cou describe what seen b x when shown to LVF sad ‘nothing there’, in split brain messages fr RH/to lang centr in LH are x relayed
ppt cou x give verbal labels to obj projected to LVF b cou select matching obj using left hand
if pin up pic shown to LVF there’s emot resp b ppts reported seeing nothing
conclus; obvs show cert funct lateralised in brain/supp view LH verbal and RH silent b emot
evaluation - lateralisation in the connected brain; hemispheric lateralisation/split brain
strength
fink et al; used PET scans to identify wh brain areas were active dur visual proc task
when ppts asked to look at global elements of image, regions of RH +re active
when ppts looked at finer details specific areas of LH dominated
TF: sugg as far as visual processing, hemispheric lateralisation is ft of connected br as well as split br
evaluation - one brain; hemispheric lateralisation/split brain
limit
LH as analyser/RH as synthesiser may be wrong
res sugg peop x have dominant side of br wh creates diff personality
nielson et al; analysed brain scans fr 1000+ peop 7-29yrs fou peop used cert hemisph for cert tasks b x evid 4 dominant side
TF: sugg that notion of right/left brained peop wrong
evaluation - research support; hemispheric lateralisation/split brain
strength
supp fr +re recent split brain research
gazzaniga; showed split brain ppt acc perf bett than connected control grp on cert tasks
ex. they’re faster at identifying odd one out in line of simi obj than norm contr
in norm br LH bett cog strateg are ‘watered down’ by inferior RH
TF: supp sperrys earlier find that L br / R br distinct
evaluation - generalisation issues; hemispheric lateralisation/split brain
limit
cas relationsh hard to establish
beh of sperrys split br ppts compared to neurotypical contr grp
how none of contr grp had epilepsy, confounding variable
any differences may be res of epilepsy than split br
TF: means some unique ft of split br ppts cog ability might been due to their epilepsy
brain plasticity - plasticity/functional recovery of the brain after trauma
br has ability to change throughout life
in infancy br experi rapid growth in nu synaptic connections, peaking at 15000 per neuron around 2-3 yrs (2x adult br)
as age rarely used connection deleted/freq ones strengthened, synaptic pruning
synaptic pruning enab lifelong plasticity where new neural connections formed
research into plasticity - plasticity/functional recovery of brain after trauma
maguire et al; stud br of london taxi drivers/fou signif +re vol of grey matter in posterior hippocampus than matching contr grp wh is part of br assoc w developm of spatial/navigat skills
part of training, t drivers take ‘the knowledge’ test wh assess recall of streets/routes
fou the longer t driver in job, +re pronounced struct differ
draganski et al; imaged brains of med stud 3 mon b4/aft exams and fou learn induced changes occur. in posterior hippocampus/parietal cortex presumably as res of learning
after brain trauma - plasticity/functional recovery of brain after trauma
following trauma, br adapts to damaged areas
funct recovery; ex neural plasticity where healthy area takes ov damaged area
neuroscientists sugg proc occ quickly aft trauma b slows down aft few weeks
brain during recovery - plasticity/functional recovery of brain after trauma
brain able to rewire/reorganise forming new synaptic connections close to damaged area
secondary neural pathways activated to enable function 2 continue
axonal sprouting; growth of new nerve endings wh connect w oth undamag nerve cells to form new neuronal pathways
denervation super sensitivity; when axons that do simi job beco aroused to high lev 2 compensate for lost neurones, however -ve conseq of over sensitivity
recruitment of homologous areas on opp side of br; specific tasks can still be perf
ex. if broca’s area damaged on LS br then RS equiv wou carry out its functions
evaluation - -ve plasticity ; plasticity + recovery
limit
evid shows brains adaptation to prolong drug use leads to poorer cog funct later in life/ incr risk dementia
60-80% of all amputees have develop phantom limb syndrome
sensation due to cortical reorganisation in somatosensory cortex
TF: sugg brain abil 2 adapt 2 damage x always beneficial
evaluation - age and plasticity ; br plasticity and recovery
strength
may be long life abil
bezzola et al; demonstrat 40 hrs golf training produced changes in neural rep. of movem in ppts aged 40-60yrs
fmri show incr motor cortex act. in golfers compar 2 grp
sugg +re effic neural rep aft training
TF: shows neural plasticity can cont thruout lifespan
evaluation - real world applic; br plasticity / recovery
strength
contrib to field of neurorehabilitation by underst axonal growth encourag new therapies
ex. constraint induced movem therapy w stroke patients, repeated practice using affected arm while unaffected restraint
TF: shows research into funct recov useful as helps medic prof know when intervent needed
evaluation - cog reserve; br plasticity/recovery
limit
lev education may influe recov rates
schnieder et al; +re time peop w br injury had in educ, greater chances of diabil free recov
40% those who achiev dfr had +re than 16 yrs educ compar to 10% those who had less than 12 yrs educ
TF: implies that peop w brain damage who have insuffic dfr r less like 2 achiev full recov
fMRI
detects changes in blood flow and oxygenation
incre neural activ = higher o2 consumption
produces 3d images showing wh parts of br involv in specific ment processes
strength of fMRI
high spatial resolution so shows wh area of br involv in partic funct so furth underst localisation of funct
don’t rely on radiation so it’s a safe method
non invasive
weakness of fMRI
may take multiple attempts as cllear image only produced if pers is still
each scan takes 45 mins so time consuming
only measures blood flow not indiv neural activ
EEG
record of tiny electrical impulses produced by the brains activ
works by fixing elctrodes to pers scalp by skull cap
used as diagnostic tool by clinicians, unusual arrhythmic patterns of activ may indicate neurological abnormalities
strengths of EEG
useful in study of epilepsy as can easily detect on screen
has high temporal resolution/accurately detect br activ at resolut of single millisec
weakness of EEG
It is not useful for pinpointing the exact source of neural activity and it does not allow researches to distinguish where activities originate.
ERP (event related potentials)
An ERP is the brains electrophysiological response to a specific motor, cognitive or sensory event.
It can be isolated through statistical analysis of EEG data.
strengths of ERP
ERPs use the same method to detect brain activity as EEGs therefore have excellent temporal resolution
cheaper than oth meth like fMRI
freq used to meas cog funct/defic
weaknesses of ERP
ERPs have a lack of standardised methodology. This makes it difficult to confirm findings. This is because pure data can only be established if background noise is eliminated as it could effect the reliability of the data.
post mortem examination
A post mortem is the examination of the body after death.
They can be used to determine whether observed behaviours during the patients lifetime can be linked to brain abnormality.
indiv br who have rare disord/unusual deficit in cog proc/beh subject to PME
strengths of PME
vital in the understanding of key processes in br
They can improve medical knowledge and help generate hypothesis for further study.
broca/wernicke: relied on PMe to establish links b/w br/beh b4 neuroimaging
weaknesses of PME
Raises ethical issues of consent as the patient is not alive to give informed consent.
ex HM lost abil to form memories so was not able to prov consent but PME conduct anyways
observed br damage may x due to deficit under review b to oth unrelated trauma/decay
Circadian rhythms: The sleep wake cycle
o Exogenous zeitgeber = daylight
o Endogenous pacemaker = SCN that lies just above optic chiasm and provides info from eye about light
o exogenous zeitgeber resets SCN
Siffre cave study
Spent extended periods of time underground to study effects on biological clock
Deprived of natural light & sound
Biological clock settled to one just beyond usual 24hrs & continued to fall asleep & wake up on regular schedule
Other research ; circadian rhythms (AO3)
Aschoff & Wever: convinced group of pp ts to spend 4wks in ww2 bunker deprived of natural light
All but 1 displayed c.rhytum btw 24 - 25 hrs
Folkard et-Al: 12 ppt who agreed to live in dark cave for 3 wks, going bed & rising at certain times
Over time researchers sped up clock, only one able to adjust, suggests strong free-running c.rhythm that can’t be easily overridden by exogenous zeitgebers
evaluation - practical application w drugs; circadian rhythms
Research has found that there are certain peaks in a day when drugs are most effective and therefore has led to guidelines about the the drug should be taken
by understanding circadian rhythms and their impact on health it can help determine the best time to administer drug treatments
evaluation - practical application w shift work; circadian rhythms
Gives researchers a better understanding of the consequences of shift work and other disrupted sleep. Research has found mistakes are most likely to be made at 6am due to a conc lapse they are also 3x more likely to suffer fr heart disease as a res of stress of adjusting to sleep/wake cycles.
TF res has economic implications in terms of maintaining worker productivity and prevnt accidents in workplace
evaluation - poor control ; circadian rhythms
Poor control: Researchers believed that the lamp would not effect the cycle. however czeisler fou that dim artif lighting cou adjust the circadian rhythm b/w 22-28 hrs
TF results may lack validity as has confounding variables
evaluation - issues w case study evid ; circadian rhythms
Use of case studies: Case studies tend to involve small groups of people which limits the extent to which the findings can be generalised.
Individual differences: can be different in different people. some people have a natural tendency to go to sleep earlier than others.
Infradian rhythms :Synchronising the menstrual cycle
Stern and McClintock: showed how m. Cycles synchronise due t influence of pheromones
o 29 women wi irregular periods, 68% experienced changes that brought them closer to cycle of odour donor
Seasonal affective disorder (sad)
depressive disorder, symptoms = low mood, lack of interest in life
Triggered in winter due to daylight hours decreasing
During night pineal gland secretes melatonin until dawn when increase light, in winter secretion happens for longer due to lack light in morning,has knock-on effect on production of serotonin in brain wh linked to dep sympt
Ultradian rhythm: sleep cycle
-5 Stages that span approx. 90 mins
- stage 1&2: light sleep, easily woken
1: alpha waves, high freq, low amp
2: alpha waves continue but occasional changes in pattern called sleep spindles
- stage 3&4: deep sleep/slow wave sleep, delta waves wi low freq high amp
- stage 5: REM sleep
body= paralysed, brain activity closely resembles that of an awake brain
theta waves, eyes move, sometimes rapidly
dreams occur but can also occur in deep sleep
evaluation - evolutionary basis; ifradian rhythms
Suggests that there is an evolutionary advantage in women menstrual cycles becoming synchronised. If a large number of women had babies at the same time they could share responsibility in rearing children. This is partially useful because if a mother is lost during childbirth another woman can breast feed.
evaluation - methodological limitations; ifradian rhythms
many factors may eff change to menstr cyc ie stress, diet change, exercise these r confounding variables
any patt synchronising no more than would be expect by chance
expla why oth stud have failed to replicate findings
TF sugg menst synchrony stud flawed
evaluation - application of SAD ; ifradian rhythms
Research means effective treatments can be found. For example phototherapy is the exposure to very bright light first thing in the morning which reduces melatonin production.
evaluation - improved understanding ; ultradian rhythms
strength
improv understanding of age related changes in sleep
sleep scientists observ SWS reduc w age, growth hormone mostly prod dur SWS TF reduc in older peop
van cauter et al, res sleep deficit may expla issues in old age ex reduced alertness
to incr SWS relaxation/medication may be used
TF: sugg ultradian rhythm knowledge has practical val
evaluation - individual differences ; ultradian rhythms
limit
ultradian rhythm res shows theres signif variation b/w peop
tucker et al; fou large differences b/w ppts in terms of duration of each sleep stg partic stg 3/4
sugg these differences likely 2 be biologically determined
TF makes diffic 2 describe ‘norm sleep’ in any meaninful way
Endogenous pacemakers & the sleep wake cycle
SCN is bundle of nerve cells, receives info about light from optic chiasm, continues even when eyes are shut to allow bio clock to adjust to changing patterns of daylight whilst we sleep
Animal studies:
- DeCoursey et al: destroyed SCN in 30 chipmunks, returned to natural habitat and observed, at end of study sleep/wake cycle disappeared & most killed
Ralph et al: bred hamsters w 20hr s/w cycle, SCN cells transplanted into brains of normal hamsters, cycles defaulted to 20hrs
SCN passes info ab light & daylength to pineal gland that secretes melatonin when dark to induce sleep
Exogenous zeitgebers & sleep/wake cycle
Resets biological clock from external factors in environment
light;
resets body’s main endogenous pacemaker, SCN
Campbell & Murphy: light may be detected by skin receptor sites on body even when same info isn’t received by eyes, 15ppts. woken at various times & light shone on back of knees, produced deviation in s/w cycle of up to 3 hrs, TF light is powerful e.z mat don’t rely on eyes to influence brain
social cues:
newborn babies s/w cycle is random, at 6wks circadian rhythm begins, at 16wks rhythms entrained by schedules imposed by parents
jet lag research shows adapting to local eating & sleeping is effective in entraining C.rhythms & beating jet lag
evaluation - ethical issues; EP
Much of the research done on exogenous Zeitgebers and Endogenous Pacemakers was on Animals and involved invasive surgeries. This would have a lot of harm on to animals and also resulted in death.
evaluation - interactionist system; EP
It is more appropriate to suggest an interactionalist system between zeitgebers and pacemakers and say that they work together rather than separately. in siffres studys he used artifical light which cou have reset his biological clock everytime he turned the lamp on
in everyday life pacem/zeitgeb interact so makes little sense to sep 2 for res
TF isolating reduces validity of research
evaluation - environmental observation; exogenous zeitgebers
limit
EZ x have same eff in all environm ex. peop who live in arctic circle have simil sleep patt all yr round despite spending 6 mon in tot darkness
TF sugg s/w cycle primarily controlled by EP that can override environmental changes in light
evaluation - case study evid; exogenous zeitgebers
miles et al; recount study of young man blind fr birth w abnormal circadian rhythm of 24.9 hrs
despite social cues ie. reg mealtimes his s/w cycles cou x be adjusted
TF: sugg that social cues alone r x eff in resetting biological rhyth
