Maguire

Question 1

Maguire’s aim

Answer 1

To examine whether brain plasticity could be detected in London taxi drivers with extensive experience of spatial navigation.

Question 2

What is the hippocampus?

Answer 2

Part of the brain responsible mainly for memory, especially long term memory. It is also important for navigation.

Question 3

What is a Voxel based morphometry (VBM) and what does it measure?

Answer 3

A procedure that identifies regional differences in grey matter density in MRI scans, showing in 3D where there were different densities of grey matter in the brain.

Question 4

What is pixel counting and what does it measure?

Answer 4

A method used to measure the size of the hippocampus. It involves counting the single points on a graphic image of a slice of the brain.

Question 5

What is a Blind Researcher?

Answer 5

A researchers and those involved in the study do not tell the participants if they are being given a test treatment or a control treatment.

Question 6

What kind of experiment was this and how do you know?

Answer 6

Maguire used a quasi-experiment as the independent variable (whether the participants were taxi drivers or non-taxi drivers) was not directly manipulated by Maguire and was naturally occurring

Question 7

What was the design of this experiment and how do you know?

Answer 7

Maguire used independent measures design as the control group and experimental group carried out individual conditions each

Question 8

What were the dependant variables?

Answer 8

-VBM (voxel-based morphometry)
<3D measure of grey matter density in MRI scans
-Pixel Count
>2D measurement. Independent (blind) count of pixels within three regions of the hippocampus; posterior, body and anterior to measure grey matter volume
-Volume of hippocampus

Question 9

Describe the participants of the experimental group

Answer 9

• 16 right-handed, male, licensed London taxi drivers
• Aged range 32–62 years (mean age 44 years)
• All had licence for at least 1.5 years (range 1.5–42 years, mean 14.3 years)
• All had healthy medical profiles

Question 10

Describe the participants of the control group

Answer 10

50 right-handed, male, non-taxi drivers,
Age range 32-62
All had healthy medical profiles

Question 11

Name controls used in this study

Answer 11

• All participants were male
• Taxi and non-taxi drivers were age matched
• All participants came from London area
• All participants were right handed
• All participants were scanned at the same unit
• Pixel counter was ‘blind’ to VBM results and whether the scan was of a taxi or non-taxi driver

Question 12

VBM results for taxi driver group

Answer 12

Increased grey matter was found in the right and left posterior hippocampi

Question 13

VBM results for non-taxi driver group

Answer 13

Relatively more grey matter volume in the right and left anterior hippocampi

Question 14

Pixel counting results

Answer 14

• No difference was found in overall volume of the hippocampus between taxi drivers and non-taxi drivers
• It showed a regionally significant difference between the left and right side of the hippocampus

Question 15

Correlation results

Answer 15

• There was a positive correlation between time as a taxi driver and volume if the right posterior hippocampus
• The length of time spent as a taxi driver negatively correlated with the volume of the anterior hippocampus

Question 16

What are conclusions made from this study?

Answer 16

• Structural brain changes in the hippocampus are likely a result of being a taxi driver, not because of a pre-existing structure which predisposes a person to become a taxi driver.
• Therefore our brains do have plasticity.
• This plasticity is useful for rehabilitation of brain-injured patients as it suggests that brain structures can be altered.

Question 17

Define: control group

Answer 17

The control group is made up of participants who do not receive the experimental treatment. These people are randomly selected to be in this group but also closely resemble the participants who are in the experimental group or the individuals who receive the treatment

Question 18

Define: experimental group

Answer 18

The experimental group is made up of participants who are/have been exposed to the independent variable (being a taxi driver).