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