Maguire Flashcards
1
Q
Aim
A
- investigate differences of hippocampus vol in London taxi drivers + non ltd
- see how far brain shows neuroplasticity when exposed to extensive navigation experience
- see if there’s correlation between taxi driving experience length & measure of grey matter vol
2
Q
Method
A
- Quasi: (taxi or not) highly controlled
- Correlation: (experience length)
- Matched pairs: minimises individual differences
3
Q
Sample
A
- 16 taxi drivers
- male, right handed
- 32-62y (mean 44y)
- healthy medical, neurological + psychiatric profiles
comparison group
- 50 control pts chosen from MRI scan database at same unit where tds scanned
- healthy, male, 32-62y
4
Q
Variables
A
- IV: taxi drivers & non-taxi drivers
- DV: hippocampus vol
- Correlational analysis: length of experience (V1) & grey matter vol (V2)
5
Q
Procedure: Voxel-Based Morphometry
A
- separates imaging of white & grey matter
- identifies differences in grey matter densities in diff brain parts
- grey matter has dense neural connections + associated w higher order of thinking
6
Q
Procedure 2: Pixel Counting
A
- pixels counted in photographic ‘slices’ made thru brain using MRI ~ calculate hippocampus vol
- pixels counted for anterior (front), posterior (back) + body hippocampus
7
Q
Controls
A
- ppts scanned using same scanner adjustments
- diff brain sizes accounted ~ all data = comparable
- expert analysers blind to ppts td/not td
8
Q
Results: Experiment
A
- td greater grey matter vol in posterior hippocampus (remember by: posture = back = I sit back of taxi)
- ntd greater vol in anterior hippocampus
9
Q
Results: Correlation
A
- longer td = more dense posterior hippocampus ~ significant positive correlation
- ~ more experience = more grey matter ANTERIOR
- significant negative correlation for anterior hippocampus
- ~ more experience = less grey matter in ANTERIOR hippocampus
10
Q
Conclusion: Experiment
A
- navigation skills in ltd associated w REDISTRIBUTION of grey matter in hippocampus
- brain plasticity ; brain structure changes in response to environmental demand
- ~ mental map of London stored in posterior hippocampus
11
Q
Correlation
A
- supports ^ ; longer experience = greater posterior hippocampus vol
12
Q
Type of Data
A
Quantitaive
grey matter density & no. Pixels measured
Scan analysis:
- Objective & replicable
- Useful for analysis & comparison
- Unbiased
13
Q
Validity
A
- High internal: controls (eg. Blind expert analyser) ensures only IV (td/ntd) impact DV (hippocampus vol)
- Low ecological: unrealistic ; brain not measured in relation to driving/navigating experience
- Concurrent Validitiy: both Quasi experiment & Correlation results support same conclusion
14
Q
Reliability
A
- High ; used accurate/scientific equipment, eg. fMRI
- standaridised procedure: all similar experience ; controls, eg. Scanned by same scanner
- BUT no measure of amount of driving done by controls
15
Q
Sampling bias/Ethnocentirsm
A
- biased ; small, all male, from London, right handed
