Maguire - Taxi Drivers Hippocampus

Background

• Brain plasticity = the brain can change based on particular experiences of the body and person

• Hippocampus = linked to conversion of information from short term to more permanent memory

  • Left side = memories of events

  • Right side = holds mental maps

• Anterior hippocampus = the front part - new learning about environmental layouts

• Posterior hippocampus = the back part - using previously learned information about environment

• Pixel Counting = analyses MRI scans in 2D, which counts pixels from each slice to get total hippocampal volume

• Voxel Based Morphometry = analyses MRI scans in 3D, identifies differences density of grey matter in the brain

  • More denser area = more neural connections = greater use of that area of the brain

Aim

Aimed to show that hippocampus in human brain is the structure associated with spatial memory and navigation

Research Method

• Quasi experiment

• Independent measures

• Matched participants as taxi drivers were matched with control group

IV and DV

• IV = Whether the ppt was a taxi driver or not

  • Was naturally occuring so cannot be manipulated

• DV = Volume of hippocampi, including anterior, body and posterior regions by measuring MRI scans of ppt’s brains

Sample + Sampling Method

• 16 taxi drivers (all healthy, right handed, male, London, mean age 44 years)

• All passed the Knowledge (test of detailed knowledge of streets in London)

• Control group = 50 non-taxi drivers, from MRI database at University College London, have same characteristics as taxi drivers

Method

• Taxi drivers + control group individually gievn a MRI scan at Univerisity College London

• VBM = measured grey matter and compared each group

• Pixel counting = compared volume of anterior, body and posterior of taxi drivers and controls

• Images were analysed by 1 person experienced in technique and blind to whether the scan was from a taxi driver or control

Results

Differences

• No significant difference in volume of body of hippocampus between both groups

• Both groups = significantly greater hippocampal volume on the right than the left

• Taxi drivers = greater volume in posterior compared to controls

  • Showing that they use more previously stored knowledge

• Control group = greater volume in anterior compared to taxi drivers

Correlations

• As time increases as a taxi driver, their posterior increases (+ve)

• As time increases as a taxi driver, their anterior decreases (-ve)

  • These results supports idea that the brain can adapt and change depending on environmental contexts - brain plasticity

Conclusions

Supports localisation of function and brain plasitcity that specific parts of the brain can adapt to prolonged environmental stimuli from factors, such as occupation