Maguire - (Brain Scans) Flashcards
What is the aim of Maguries study?
To look at morphological change in a healthy human brain associated with spatial memory and navigation. The prediction is that the hippocampus is the most likely region to show morphological changes
What is Maguires study’s approach?
Physiological
Who were the participants within Maguires study?
16 right-handed, male London taxi drivers with a mean age of 44 and a range from 32-62. There was even spread of ages in each age group and all were taxi drivers for 1.5 yrs
There were a control group of 16 males of whom none were taxi drivers and all were the mean age and had the same age range
What two image analysis methods were used in Maguires study?
Voxel-based Morphology & Pixel-Counting
How was data collected for Maguires study?
Collected from MRI scans
What is Voxel-Based Morphology used in Maguires study?
Comparing every brain in order to identify overall differences in brain size between the brain-being-studied and the template brain.
It identifies differences in the density of grey matter in different parts of the brain
What is Pixel counting which was used in Maguires study?
The pixels are counted using images available of the brain. Total hippocampal volume was calculated by adding up the pixels from each slice and multiplying this by the distance between adjacent slices.
How was VBM used in Maguire’s study?
The template was generated from 50 healthy males. The brains of the experimental and control groups were then compared to this template. This was done to calculate the volume of different regions in the brain
How was Pixel-counting used in Maguires study?
The images were analysed by one pixel-counting professional. This person was blind to the VBM findings as well as the group in which the ‘brain’ was in
What were the results of the VBM used in Maguires study?
The R&L posterior hippocampi were significantly larger in the taxi drivers than the control groups. No differences anywhere else.
In the controls there was grey matter in the anterior hippocampi in both hemispheres of the brain
What were the results of the pixel-counting used in Maguires study?
No difference between inter cranial volume and total hippocampal volume.
Control group: larger Anterior & body of the RH
Taxi Drivers: larger posterior LH & RH
What were the changes with navigation experience of taxi drivers in Maguires study?
Time spent as a taxi driver was positively correlated with the volume of the posterior RH while negatively correlated with the volume of the anterior RH and LH
