Techniques used to study the brain in relation to behaviour - SAQ

Question 1

How was brain research done?

Answer 1

Limited to studying victims of strokes or accident and using invasive methods such as autopsy to study their brains.

This is how Broca’s area was discovered for example.

Question 2

What does MRI stand for?

Answer 2

Magnetic resonance imaging

Question 3

How are today’s techniques better?

Answer 3

They are less invasive

Question 4

What is the MRI mostly based on?

Answer 4

The principle that some atomic nuclei - in particular those of hydrogen atoms - can emit energy when placed in an external magnetic field.

Question 5

What happens when the pulses of energy are detected by the scanner?

Answer 5

The relative distribution of hydrogen atoms in the brain can be mapped.

Question 6

Why do we focus on hydrogen atoms?

Answer 6

Hydrogen atoms exist naturally in the body, but their concentration in different types of tissue is different.

Water and fat have the highest concentration.

Analysing the pattern of emission of energy in response to magnetic fields, we can see inside the brain.

Question 7

What study is used for MRI?

Answer 7

Maguire

Question 8

When was the Maguire study?

Answer 8

2000

Question 9

What is the aim of Maguire (2000)?

Answer 9

To see whether the brains of London taxi drivers would be somehow different as a result of their exceptional knowledge of the city and the many hours that they spend behind the wheel navigating the streets of London.

Question 10

What was the sample?

Answer 10

16 right-handed male London taxi drivers.

Question 11

How were the participants chosen?

Answer 11

Had to have completed the “Knowledge” test and have their license for at least 1.5 years

Question 12

To who were the taxi drivers compared to?

Answer 12

50 right-handed males who did not drive taxis

Question 13

How were they compared?

Answer 13

Compared using MRI scans

Question 14

From where were the control participants taken from?

Answer 14

Were taken from an MRI database

Question 15

What were the 2 different techniques used to analyse the MRI scans?

Answer 15

Voxel-based morphometry (VBM)

Pixel counting

Question 16

Voxel-based morphology (VBM)

Answer 16

Used in this study to measure the density of grey matter in the brain

Question 17

Pixel counting

Answer 17

Consists of counting the pixels in the images provided by the MRI scans in order to calculate the area of the hippocampus

Question 18

Results from the pixel counting

Answer 18

The pixel counting showed that the posterior hippocampi of taxi drivers were significantly larger relative to those of control subjects and the anterior hippocampi were significantly smaller.

Question 19

Results from the Voxel-based morphometry (VBM)

Answer 19

VBM showed that the volume of the right posterior hippocampi correlated with the amount of time spent as a taxi driver.

No differences were observed in other parts of the brain.

Maguire argues that this demonstrates that the hippocampus may change in response to environmental demands.

Question 20

What to know for techniques used to study the brain in relation to behaviour

Answer 20

How was brain research done?
MRI - based on, used
Why are hydrogen atoms important
Maguire (2000)

Question 21

Strength of MRI

Answer 21

There is no radiation exposure

MRI has a better spatial resolution that CAT

Question 22

Limitations of MRI

Answer 22

Due to its high resolution, the scanner sometimes picks up slight abnormalities in the brain that are not related to he original complaint. this may create anxiety and cause people to pursue unnecessary treatment

Due to the strong magnetic fields, people with metal in their body cannot undergo the procedure.

No good for people with claustrophobia as it is a small space

Expensive

Difficult for small children

Question 23

What happens after excitation?

Answer 23

After excitation by the magnetic field each tissue returns to its equilibrium state - and the time required to do so differs in different types of tissue.

Question 24

What does MRI use?

Answer 24

MRI uses a high resolution three-dimensional image of brain structure.