brain plasticity: blakemore & cooper and maguire et al

Question 1

blakemore & cooper method?

Answer 1

lab expt, imd

iv: environment reared in (horizontal/vertical)
dv: visuomotor tests and neurophysiological tests

Question 2

blakemore & cooper sample?

Answer 2

laboratory reared kittens housed in complete darkness until 2 weeks old

randomly allocated to two conditions, one from each condition used for neuro physical tests

Question 3

blakemore & cooper procedure?

Answer 3

from 2 weeks old to 5 months, the kittens spent five hours a day in their ‘world of stripes’

2m by 46cm cylinder with clear perspex floor 1m up

kittens wore a black collar so they couldn’t see their own bodies

after 5 months, they spent time in a well lit room to be assessed (startle response, visual paw placement, responses to rods held v/h)

125 neurons tested for neuro physical effects

Question 4

blakemore & cooper behavioural results?

Answer 4

despite normal pupil reflexes to light, kittens displayed visual defects, navigating through touch rather than light, no evidence of visual paw placement

failed to show no startle response and showed fear when reaching the edge of surfaces

a lot of these problems disappeared after 10 hours in a brightly lit room, but some stayed, continuing to bump into furniture and clumsily following objects

kittens only responded to perspex sheets and rods corresponding to their environment

Question 5

blakemore & cooper neurophysical results?

Answer 5

normal cat has balance of horizontal and vertically dedicated neurons

kittens from vertical environments had no neurons within 20 degrees of the horizontal, and vice versa

Question 6

blakemore & cooper conclusions?

Answer 6

the difference between horizontal and vertical kittens suggests neurons change in response to their early visual experience

thus, brain development responds to early environmental factors

establishes role of nurture in development of sight (at least for cats)

Question 7

blakemore & cooper method evaluation?

Answer 7

lab expt, high levels of control

could manipulate & control conditions

environment for assessment of behaviour and materials were also controlled

Question 8

blakemore & cooper data collected evaluation?

Answer 8

quantitative: results from neurophysical analysis, different conditions can be statistically analysed
qualitative: provides detailed descriptions of conditional responses

Question 9

blakemore & cooper ethicality evaluation?

Answer 9

complies with home offices laws surrounding research concerning animals, however suffering of the kittens was inevitable and one from each condition was euthanised

ethics of animal research uses bateson’s cube

Question 10

blakemore & cooper validity evaluation?

Answer 10

highly controlled conditions, kittens in darkness between sessions, can determine cause (the iv) and effect

effects of iv assessed two ways, concurrent validity

Question 11

blakemore & cooper sampling bias evaluation?

Answer 11

use of cats means that generalisation to humans should be done with caution, issue with population validity

Question 12

blakemore & cooper link with theme?

Answer 12

links to brain plasticity by demonstrating how a cat’s visual neurons develop an orientation reliant on the conditions they grew up in between the ages of 2 weeks to 5 months

cats who grew up with horizontal stripes develop neurons up to 20 degrees of the vertical, and vice versa

Question 13

blakemore & cooper link to area?

Answer 13

assumption: all behaviour is first physiological

shows a definite link between the orientation of neurons in a kitten’s brain, and the behaviour this cat exhibits

Question 14

maguire method?

Answer 14

quasi experiment, imd

data collected via mri for correlational analysis

Question 15

maguire experimental sample?

Answer 15

16 right handed, male, london taxi drivers

mean age 44 (32-62)

licenced for at least 1.5 years (1.5-42 years, mean - 14.3)

average of 2 years on the knowledge

healthy medical, neurological and psychiatric records

Question 16

maguire control sample?

Answer 16

selected scans from 50 individuals

all male, right-handed, non-taxi drivers

mean age and range matched to expt group

no one with health problems

Question 17

maguire procedure?

Answer 17

voxel-based morphometry (grey matter volume)

pixel counting (hippocampal volume in relation to brain size)

counts performed by ‘blind’ expert

correction made to account for different brain sizes, using intercranial volume

Question 18

maguire vbm results?

Answer 18

taxi drivers showed increase in grey matter in the left and right hippocampi

bilateral increase in posterior hippocampi but bilateral decrease in anterior hippocampi

Question 19

maguire pixel counting results?

Answer 19

found no difference in overall hippocampal volume of expt and control groups

regional differences were recorded however, with taxi drivers having bigger posterior regions and smaller anterior regions

Question 20

maguire correlation results?

Answer 20

saw a positive correlation between right posterior hippocampi volume and years as a taxi driver

also found a negative correlation between right anterior hippocampi volume and years as a taxi driver

no correlation for left hippocampus

Question 21

maguire conclusions?

Answer 21

suggests a relationship between navigational skills and distribution of grey matter in the hippocampi

posterior hippocampus: previously learnt spatial information

anterior hippocampus: encoding new information (also involves post.)

taxi drivers require a mental map of london, which needs an increase in volume

suggests left has a different role to right hippocampus, perhaps to store episodic memory

Question 22

maguire method evaluation?

Answer 22

highly controlled lab expt

however quasi design could lead to participant variables, although matching minimised this

mri scanning precise and objective, but expensive and machines and technicians have limited availability

correlational analysis can confirm a relationship, but not causation

Question 23

maguire data collection evaluation?

Answer 23

only quantitative, allows statistical analysis and correlation

however, lacks detail

Question 24

maguire ethicality evaluation?

Answer 24

carried out to bps guidelines

no deceit, informed consent given, right to withdraw ensured, no harm (bar claustrophobics and those with metal implants)

Question 25

maguire validity evaluation?

Answer 25

despite quasi nature, ps being matched on age, sex and handedness increased design validity

concurrent validity from pixel counting and vbm

conclusions are supported by the correlation and animal research

no possibility of demand characteristics, so no worry of ecological validity due to lack of a task

blind technicians increased validity of dv measures

Question 26

maguire sampling bias evaluation?

Answer 26

androcentric, can’t assume male and female brains function the same way

spatial memory of left and right handed people may work differently

taxi drivers chosen may be those more adaptable to the knowledge as they all completed it with an average of 2 years

Question 27

maguire link to theme?

Answer 27

links to theme of brain plasticity by showing how an adult brain can adapt to the environmental demands placed upon it

in this case, it was the taxi drivers brains developing a larger posterior hippocampus and smaller anterior hippocampus

Question 28

maguire link to area?

Answer 28

focuses on brain structures, functions and these can change under certain conditions

studied the neuroplasticity of taxi drivers and demonstrating how different regions of the hippocampi react to having to accomodate large amounts of spatial information

Question 29

blakemore & cooper and maguire similarities?

Answer 29

both highly controlled lab expts

both produce objective, quantitative data from biological means

Question 30

blakemore & cooper and maguire differences?

Answer 30

maguire is a quasi expt and blakemore & cooper was a true expt

maguire studied human brains and blakemore & cooper studied kittens