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Describe how the brain shows plasticity in response to external stimuli…
Describe how the brain shows plasticity in response to external stimuli
Maguire et al (2000)
Aim
To investigate whether or not the brain of taxi drivers differs from the brain of regular functioning people as a result of their exceptional knowledge of the city map.
Method
quasi experiment, MRI scans
Participants: 16 right-handed taxi drivers, 50 right-handed regular functioning people
correlational study: the independent variable was not manipulated
single blind study: the researcher did not know if they were looking at the brain image of a taxi driver or non-taxi drivers
Findings
The posterior hippocampi of the taxi drivers were significantly bigger than that of the regular citizens
The right posterior hippocampi correlated with how long the taxi drivers were in their jobs
Procedures
Researchers compare MRI scans between taxi drivers and regular citizens to investigate the different brain structures
Outcome
The hippocampi adapts to certain environmental demands
Evaluation
Validity
Is limited to one gender and right-handed people
Used a wide range of age to improve generalizability
Ethical considerations
Study is ethical
Extraneous variables
Genetics may affect brain structure
Bremner (2003)
method
Correlation study
33 women
10 with early childhood sexual abuse and PTSD
12 with abuse and without PTSD
11 without abuse or PTSD
MRI scans, memory test, PET scan
methodology
33 women participated in this study, including women with early childhood sexual abuse and PTSD (N=10), women with abuse without PTSD (N=12), and women without abuse or PTSD (N=11). Hippocampal volume was measured with magnetic resonance imaging in all subjects, and hippocampal function during the performance of hippocampal-based verbal declarative memory tasks was measured by using positron emission tomography in abused women with and without PTSD.
findings
A failure of hippocampal activation and 16% smaller volume of the hippocampus were seen in women with abuse and PTSD compared to women with abuse without PTSD. Women with abuse and PTSD had a 19% smaller hippocampal volume relative to women without abuse or PTSD.
outcome
aim
To investigate if increased stress will decrease hippocampus volume due to high cortisol levels.
evaluation
stregths
Ecological validity is high,
Method triangulation was used
MRI scans show a high resolution image and it is a non-invasive procedure
limits
Asking participants to recall traumatic experiences can lead to mental harm
.
As the sample size is small the findings cannot be generalized.
ANSWER