Ways of investigating the brain Aims: What are the different ways in which the brain can be studied? How can these methods be applied? What is strong/weak about these methods?

Prep task sheet

What questions could you ask about ways of studying the brain?

1. Functional Magnetic Resonance Imaging Identifies which brain areas are more active during a task

Functional Magnetic Resonance Imaging https://www.youtube.com/watch?v=nvB9hAarzw4 How does MRI work? What equipment is used? What’s the procedure? How safe is it?

How does fMRI work in detail? https://www.youtube.com/watch?v=Rb_mdzgw-Jc Make notes under the following headings Blood “haemodynamic response” Spin Magnetic Field Disturbances

How it works BASIC PRINCIPLES OF MRI The magnetic field and radio waves inside the scanner affect the nuclei of hydrogen atoms in your body. Normally, nuclei are randomly oriented but under the influence of a magnetic field the nuclei become aligned with the direction of the field. When pointing in the same direction, the tiny magnetic signals from individual nuclei add up, resulting in a signal that is large enough to measure (Magnetic Resonance). The key to MRI is that the signal from the hydrogen nuclei varies in strength depending on its surroundings. This provides a means of discriminating between grey matter, white matter and cerebral spinal fluid in structural images of the brain.

How it works WHAT FMRI MEASURES Oxygen is delivered to neurons by haemoglobin in red blood cells. When neuronal activity increases there is an increased demand for oxygen and blood flow to the area. There are small differences in the magnetic resonance (MR) signal of blood depending on the degree of oxygenation. Differences in blood oxygenation can be used to detect brain activity & create images.

Knowledge Check & Refresh Outline how an fMRI works as a way of studying the brain. (5 marks) Once you have completed your answer, use your notes to compile a brief mark scheme. Check your neighbour’s answer against your mark scheme. Stretch & Challenge Once you have outlined the above answer, take it down to a 3 mark answer. What key elements would you need to keep/summarise further, and which would you cut out?

2. Electroencephalogram (EEG) Scalp-recorded fluctuations in the brain’s electrical activity

2. Electroencephalagram (EEG) https://www.youtube.com/watch?v=1ovv6lmPHSI Make notes on: What the EEG is recording Strengths / limitations Equipment used

Check your notes – key points The EEG records the electrical activity of thousands of millions of neurons in the cortex by placing electrodes all over the pp’s head. A number of recording electrodes are placed over the scalp, while a reference electrode is placed at some distance from the recording electrode, on the nose/forehead. The EEG waves are recorded and presented on a computer screen. Each recording represents the potential differences between the recording electrode and the reference electrode

Ways to impress the examiner – little extra details, such as: The EEG technique is used for recording various mental states such as wakefulness, drowsiness, and stages of sleep. Also used for identifying brain tumours or for clinical analysis of epilepsy or coma. The EEG is a non-invasive technique that is characterised by high temporal (time) resolution but low spatial (locational) resolution

3. Event Related Potentials (ERPs) Brief changes in EEG elicited by a discrete sensory stimulus

Imagine throwing a stone into choppy water…could you see the splash? One problem with identifying where the ERP is coming from is that it’s there’s so much background noise

https://www.youtube.com/watch?v=NTC8f7zWPQk Make notes on how ERPs are used to detect lies

Check your notes: ERP steps Summates/finds average background “noise” Specific stimulus (aural or visual) is presented Background ‘noise’ is removed You are left with a precise area of brain activity responding to the stimulus

4. Post-mortems Surgical analysis of a brain after death. Usually done on people with rare disorders or those who have experienced unusual cognitive or behavioural deficits. Can examine areas of damage or structural differences to neurotypical brains https://www.youtube.com/watch?v=cqmZFoGvzfU Einstein’s brain removed post-mortem without consent of family. Can’t find any agreement on the actual structural differences found. Image is hyperlinked to Wellcome Trust’s dissecting brains video.

Evaluate the techniques For each method, outline at least one strength and one weakness. Aim to create a PEE(L) structure to ensure you’re clear. State your Point Evidence to back it up (research or facts) Explain clearly how this evidence supports your point For extra Brownie points… (for some points, it is possible to) 4. Link to broader issues – e.g. practical applications, validity, reliability, ethics etc

Evaluate the techniques For each method, outline at least one strength and one weakness. Aim to create a PEE(L) structure to ensure you’re clear. State your Point Evidence to back it up (research or facts) Explain clearly how this evidence supports your point For extra Brownie points… (for some points, it is possible to) 4. Link to broader issues – e.g. practical applications, validity, reliability, ethics etc

5 mark Describe questions Annotate the model answer with what it is doing. Then compare yours and do the same. Improve yours in any ways it needs to achieve top band.