Methods of studying cortical specialisation



Methods of studying cortical specialisation

Psychologists have developed many methods of studying cortical specialisation in the brain in order to be able to predict, control and explain human behaviour.

The Early Days

Franz Joseph Gall (1758-1828) developed a technique called phrenology. This basically means that they would feel for ‘bumps’ on the heads of patients and attribute these to particular psychological characteristics. This technique was discredited for a lack of scientific evidence.

Today: various invasive and non-invasive methods are used in order to explore and develop our understanding of areas of cortical specialisation

TASK:

In your groups you need to make notes on all of the different methods of cortical specialisation along with their strengths and weaknesses. Each person, by the end of the lesson, needs to leave with a complete set of notes on ALL of the following things.

Pages 28/29 of the textbook have been scanned in and these contain all of the information you need, be sure to add in as many pictures of each scan as possible, they need to look distinctive so you will remember the differences between them!!

1. Invasive methods:

Post-mortem studies

2. Non-invasive methods:

Electroencephalogram (EEG)

Scanning:

Computerised axial tomography (CAT)

Positron emission tomography (PET)

Magnetic resonance imaging (MRI)

3. Strengths and limitations of methods used to investigate cortical specialisation

HOMEWORK QUESTION

January 2009

1 (d) Discuss two of the following methods that have been used to investigate areas of cortical specialisation in the brain:

• Post-mortem studies

• EEGs

• Scanning techniques

MARK SCHEME

[10 marks: AO1 = 5, AO2 = 5]

AO1 Up to five marks for a description of two methods used to identify areas of cortical specialisation in the brain.

Post-mortem examinations – a method in which the brain of a patient, usually with some known deficit, is examined after death.

Scanning techniques – PET assesses metabolic activity in different parts of the brain;

CAT shows horizontal sections of the brain; MRI gives a clear and detailed picture of brain structures.

EEG – non invasive measurement of electrical avidity of the brain by recording from electrodes placed on the individual’s scalp. Allows neuroscientists to study brain function by recording brain activity,

Credit description of relevant evidence up to two marks.

AO2 Candidates should discuss the methods described in AO1.

Post-mortem examinations – able to attribute abnormalities in brain with known deficit in patient; repeated examinations produce a more exact correlation; furthers understanding of the brain; difficulty in obtaining a human brain especially if the known deficit is particularly rare; difficulty in locating precise area of damage.

Scanning techniques – provides detailed pictures of areas of brain responsible for certain actions; patient is able to perform tasks whilst conscious; can be non-invasive; issues of injecting radioactive substance with PET scans – invasive procedure; does not always measure precise neuronal activity.

EEG – no intervention is necessary, therefore natural measurements of brain activity are allowed, electrodes are not sensitive enough to pick out individual action potentials of single neurons.

Credit use of relevant evidence.

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