bio approach: MRI - techniques to study B&B

Question 1

neuroimaging techniques have allowed?

Answer 1

psychologists and researchers to study the brain in a non-invasive way.

Question 2

an eg. of neuroimaging technology & what it does

Answer 2

MRI - allows psychologists to look at the structure of the brain by using magnetic fields and radio frequency to form images (cross sectional) of the brain.

Question 3

use of magnetic fields

Answer 3

by applying a very strong magnetic field to the brain, the MRI causes protein spins in the hydrogen atoms to align to the magnetic field polarisation.

(hydrogen is present across the brain as so much of the brain is made of water).

Question 4

use of radio frequency

Answer 4

certain hydrogen atoms are not affected by magnetic field polarisation thus MRI uses a certain radio frequency pulse which results in protein spins of atoms not previously affected.

Question 5

static image created:

Answer 5

• through a combination of different snapshots of the brain.
• it can be 2D or 3D
• can be manipulated to certain areas of interest
• indicates structure, not function

Question 6

MRI scans can:

Answer 6

• show tumours, bleeding in the brain, nerve injury and other problems caused by a stroke.
• show changes in the sizes of particular brain structures in response to learning or environment.
• be used to investigate changes in grey matter near surface of the brain.

Question 7

MRI is linked to the study?

Answer 7

Draganski et al. (2004)

Question 8

draganski et al (2004) aim -

Answer 8

to see whether learning a new skill - in this case juggling - would affect the brains of participants.

Question 9

draganski et al (2004) sample -

Answer 9

24 volunteers (21 F, 3 M) between the ages of 20 to 24.

Question 10

draganski et al (2004) procedure -

Answer 10

each P had an MRI scan at the start of the study to serve as a base rate for grey matter and brain structure.

juggling condition - taught a three-ball cascade juggling routine. they were asked to practice this routine and to notify the researchers when they had mastered it. at that point, the jugglers had a second MRI scan. after the second scan, they were told not to juggle anymore. then a third and final scan was carried out three months later.

non- jugglers -> control group.

MRI scans: identify the part of the brain involved in the formation of visual memory. to analyze the MRI scans, the researchers used voxel-based morphometry [VBM] to determine if there were significant differences in neural density (grey matter) in the brains of jugglers vs. non-jugglers.

Question 11

draganski et al (2004) results -

Answer 11

first, MRI scans of both groups showed no significant regional differences in the grey matter between the two conditions.

However, at the end of the first part of the study (after mastery), the researchers observed a significant bilateral expansion in grey matter in the mid-temporal area (hMT/V5) and the left posterior intraparietal sulcus for the juggler group.

3 months after the participants stopped juggling - when many were no longer able to carry out the routine - the amount of grey matter in these parts of the brain had decreased.

however, the jugglers still had more grey matter in these areas than at the first brain scan (before they started juggling).

no change throughout the study in the non-juggling sample.

Question 12

conclusion -

Answer 12

grey matter grows in the brain in response to environmental demands (learning) and shrinks in the absence of stimulation (lack of practise). causality relationship b/w learning & brain structure established.

supports theory of neuroplasticity - brain appeared to change in response to learning.

shows how neuroimaging techniques such as MRI can study the brain (by looking at its structure) in a non-invasive and ethical way.