biological area case study Flashcards
what was the aim of sperry’s study?
to investigate the psychological effects of hemispheric deconnection in patients with severe epilepsy
how the LH and RH work in individuals with an intact brain
what was the sample i Sperry’s study?
11 patients - split brain - referred to white memorial centre in los Angeles
what was the sampling method in Sperry?
opportunity
what was the design in sperry?
snapshot study - controlled observation
independent groups design
quasi experiment
what is the iv in Sperry?
presence of split brain
what is the dv in sperry?
pps performance on visual and tactile tests
what was the procedure in sperry- visual?
Visual investigation
. in vision - input from left half of each eye goes to the RH and input from right part of the eye goes to LH
. so if an apple is presented on left visual field (LVF) - goes to the right part of each eye - goes to RH
. if an apple was presented on RVF - goes to the left part of each eye - goes to LH
. pps asked to cover one eye and fix their gaze on one central fixation point
. image projected for 1/10 second to either LVF, the RVF or both - too fast for eyes to move and take info by both visual fields
. then they were asked to :
. report verbally what they had seen
. draw a picture of what they had seen
. pick an image from an array of pictures/objects
what was the procedure for sperry - tactile ?
.pps presented with objects in right hand, left hand or both without being able to see what the object was - hands were screened from view
. following presentation pps asked to:
. report verbally what they have seeb
. draw a picture of what they have seen
. pick an image out from an array of pictures/ objects
what was a control variable during sperry’s experiment?
remain silent unless questioned by the experimenter - prevent info from passing between hemispheres as sound can be taken in by both ears simultaneously
what were the findings in sperry’s visual experiments?
. when the fish was presented to the RVF - go to the LH- patients can say what they have seen
. draw what they have seen with the right hand
. pick it from an array of objects with the right hand
when an apple was presented to the LVF - go to RH- patients can:
. draw what they have seen with the left hand
. pick it from an array of objects with left hand
what were the conclusions from sperry’s visual experiments?
if patients were presented with na image to LVF - unable to name object - gone to RH - no longer has language capabilities. show some understanding - able to draw it with left hand
. if image show to RVF- gone to LH - patient is able to verbally name the object and can draw it with right hand
what were the findings from sperry’s tactile investigations?
. when the right hand was presented with an object - goes to LH - patients can:
. say what they have felt
.draw what they have felt with right hand
. pick it from an array of objects with right hand
when the left hand was presented with an object - goes to RH - patients can:
. draw what they have felt with left hand
. pick it with an array of objects with left hand
what were the conclusions from Sperry’s tactile investiagtions?
patients presented with object in left hnad - unable to name object because it has gone to the RH - no language capabilities -some understanding - can draw it with left hand
. object placed in right hand - LH- able to verbally name object - cna draw it with right hand
what were the conclusions from sperry’s study?
.split brain patients will not be effected in their everyday life- visual info would go to both visual fields bu moving head or eyes
. the symptoms of hemipshere disconnection are
. short term memory loss
.orientation problems
. tend to fatigue more quickly when reading
. poor mental concentration
. reduced performance at upper limits
study gave support to idea that brain consists of two independent hemispheres - no transfer of information without corpus callosum
. corpus callosum help different region sof the brain communicate
what were sperry’s conclusion about the LH?
. speech and writing
. comprehension
.organisation of language
. can communicate experiences verbally
. dominant hemisphere
what were sperry’s conclusions about the RH?
. cannot express itself verbally
.superior spatial ability
. emotional responses
. can comprehend and express its understanding using non verbal methods
how does sperry relate to the key theme of regions of the brain?
sheds light on function of the corpus callosum - importance as a communication pathway between hemispheres
example- tasks split brain patients could not perform under sperry’s strictly controlled conditions - could be done easily by a normal brain - normal brains corpus callosum was intact - two sides of their brain could still communicate
.study showed LH and RH performed separate functions - RH can control tactile abilities of left hand - LH cannot
how does Sperry relate to the biological area?
.investigating regions of the brain and lateralisation of function
. demonstrated the importance of the corpus callosum as a communication pathway between hemispheres - provided evidence of the different functions of the hemispheres
. example - LH produces language - when visual stimuli was presented to RVF - goes to LH - pps could say what they have seen - if presented to LVF - goes to RH - pps was unable to say what they have seen
describe casey’s sample in experiment 1
59 pps - 32 high delayers and 27 low delayers
what type of study was casey’s?
longitudinal study
born between 1960- 1970
first tested at age four - the in twenties - then thirties
how many pps were in casey’s original sample?
562 - all tested at age four
how many pps were in casey’s 1993 follow up?
155
how many pps were in casey’s 2003 self control self reports
135
what were the aims of casey’s study ?
if pps who were low delayers on the marshmallow test at age 4 and reported low on the self control report in 20’s and 30’s (low delayers):
. would show more mistakes on the go/no go tasks if the stimuli was hot (rewarding happy faces - would click them when they weren’t supposed to) than the high delayers
what did the researches predict that the fmri scans would show while completing the go/no go for low delayers?
.lower activity on their inferior frontal gyrus (lower response inhibition to stimuli)
and increased activities in ventral striatum - where positive or rewarding cues are processed - compared to high delayers
what is the inferior frontal gyrus responsible for?
accurately withholding a response
what is the ventral striatum?
reward related region of the brain
what is a low delayer?
low self control
have higher activity is hot go/ nogo trials in ventral striatum - less in frontal gyrus
what is a high delayer ?
high self control
less errors in the hot no/go trials compared to low delayers
what was the procedure in casey’s
