bio approach: localisation of function

Question 1

theory of localisation states that?

Answer 1

certain areas of the brain are responsible for certain psychological, physiological and behavioral functions.

Question 2

research into localisation…

Answer 2

has not been entirely conclusive.

now neuroscientists believe functions are localised but the idea of strict localisation has been gradually replaced by the idea of relative localisation.

Question 3

strict localisation definition:

Answer 3

the idea that there is a clear correspondence between these functions and brain areas, and that all functions can be clearly mapped back to the brain.

Question 4

relative localisation definition:

Answer 4

the idea that several brain areas are responsible for the same function (and can potentially take over) but only one of these areas are dominant.

Question 5

localisation is studied by?

Answer 5

Draganski et al. (2004)

Question 6

draganski et al (2004) aim -

Answer 6

to see whether learning a new skill - in this case juggling - would be traced back to certain areas of the brain.

Question 7

draganski et al (2004) sample -

Answer 7

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

Question 8

draganski et al (2004) procedure -

Answer 8

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 9

draganski et al (2004) results -

Answer 9

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 10

conclusion -

Answer 10

observed changes in grey matter were bilateral, occuring on both sides of the brain. this bilateral expansion in the mid-temporal area and the left posterior intraparietal sulcus suggests multiple brain areas were involved in the response to the learning and practise of juggling. - engages distributed neural networks rather than localisation to a single region

thus supporting theory of relative localisation as multiple brain regions are involved in the cognitive processes such as hand-eye coordination, spatial memory and visual memory that are associated with juggling.