Biological area ( Maguire) Flashcards
what is brain plasticity
It is the ability of the brain to adapt in response to changes in demand from the environment.
grey matter
is tissue in the nervous system that appears grey because it is composed of numerous nerve cell bodies. This is involved in processing information in the brain.
white matter
appears white due to the fatty myelin insulation on the neurons. This transfers information to other locations.
background
The Hippocampus is an important part of the brain which is involved in memory and navigation.
aims
to investigate the differences in the hippocampi of London taxi drivers compared to controls
also to further investigate functions of the hippocampus in spatial memory
participants
16 male London taxi drivers
all right handed
between 32 and 62 years
Been licensed for at least 18 months (range: 18 months to 42 years)
All passed ‘The Knowledge’
All healthy medically, neurologically and psychologically
control group
Participants were needed to compare to the taxi drivers (the experimental group).
Researchers selected 50 scans from the MRI database at the centre where the taxi drivers were scanned.
All were healthy right-handed males aged between 32 and 62.
None of the control scans was from taxi drivers.
pixel counting
his was carried out by one experienced analyst who did not know whether the scan came from a taxi driver or a control participant.
A pixel is a 2D measure of area (i.e. the number of individual dots that make up the image).
The scans were separated into 26 ‘slices’ of the hippocampus – and the number of pixels in the posterior/anterior and main body counted so differences in these areas could be detected.
Voxel-based morphometry (VBM)
This is an objective 3D measure of the volume of grey matter in the brain (calculated from the MRI scans by computer). The computer program looks at all the slices together and calculates if there are any differences in volume of grey matter.
results
Significantly increased grey matter volume was found in the taxi drivers’ brains compared to the controls’ brains in both sides of the posterior (back) hippocampus.
But they also showed lower volume in the anterior (front) hippocampus
conclusions
The study showed regional differences between the hippocampi of London taxi drivers compared to a control group of non-taxi drivers.
It seems that relying on navigational skills as part of your job is associated with a redistribution of grey matter in the hippocampus (from the anterior to the posterior hippocampus).
