Ways of Researching the Brain

Question 1

What are the four ways of studying the brain:

Answer 1

• post mortem examinations
• functional magnetic resonance imaging (fMRI)
• electroencephalogram (EEG)
• event related potentials (ERP)

Question 2

Post-mortem analysis:

Answer 2

ANALYSIS OF A PERSON’S BRAIN AFTER THEIR DEATH.
- Researchers study a person’s unique/ abnormal behaviour whilst they’re alive
- After death, analyse structure of the brain by comparing it to a neurotypical brain to ascertain which parts are not functioning well
- Helps researchers work out which part of the brain is abnormally structured
- Areas of the brain which are found to be damaged during PMA seen as correlated with abnormal behaviour
- If participant was not studied while they were alive (i.e. no primary data) data is gathered about their behaviour from secondary sources

Question 3

What do researchers compare the brain to?

Answer 3

a neurotypical brain to ascertain which parts are not functioning well

Question 4

If the ppt was not studied while they were alive, what data is gathered abt their behaviour?

Answer 4

secondary

Question 5

Strength of PMA: allows for detailed examination of anatomical and neurochemical features compared to non-invasive methods such as fMRI.

Answer 5

This is bc you can physically assess the brain parts - unlike techniques like fMRI that can only visualise them as a diagram. This gives us precise info abt brain regions / neurochemicals involved in particular behaviours.
Increasing the validity of PMA

Question 6

Strength Of PMA evidence: was crucial in building first understanding of key brain processes.

Answer 6

E.g Paul Broca used PMA to establish the link between language and brain by showing an area of the frontal lobe is related to language production.
Helped add scientific credibility to study of relationship between brain + behaviour / cognition which allowed for hypothesis testing using empirical evidence.
Increasing validity of PMA

Question 7

Weakness Of PMA: data is retrospective.

Answer 7

If interesting findings r discovered in structure of brain during PMA, cannot follow up to gather further data on beh.
Also possible that damage to brain areas could be due to unrelated trauma or decay after death - could lead to inaccurate conclusions about which parts of the brain are linked to the abnormal beh

Question 8

Weakness Of PMA: the sample sizes are generally small.

Answer 8

Small sample sizes and samples consist of unique patients - results cannot be generalised to the wider population.
Decrease validity

Question 9

fMRI

Answer 9

functional magnetic resonance imaging

Question 10

Functional Magnetic Resonance Imaging

Answer 10

fMRI BASED ON THE PRINCIPLE THAT THE MORE ACTIVITY IN AN AREA OF THE BRAIN -> HIGHER BLOOD FLOW TO THAT AREA OF BRAIN BC TO MAINTAIN HIGH ACTIVITY IN THAT BRAIN AREA: OXYGEN and NUTRIENTS ARE NEEDED TO BE SUPPLIED BY THE BLOOD
- fMRI scanners use magnetic field and radio waves to measure changes in blood flow + oxygenation caused by neural activity.
- Specifically measures change in energy released by haemoglobin - used to identify which areas are active and consuming more oxygen
- Scans are presented as 3D activation map - identify active brain parts + localised functions
- To identify activity, ppts go through an experimental task (e.g identifying faces) and the brain activity in response to the exp task is compared to the brain activity in response to the baseline task (e.g. looking at a cross)
- Areas with higher oxygen consumption = stronger brain activity. These show up as YELLOW/RED on the activation map.

Question 11

What do fMRI scanners use to measure changes in blood flow and oxygen

Answer 11

magnetic field and radio waves

Question 12

What realeases energy in the blood?

Answer 12

Haemoglobin

Question 13

What are fMRI scans presented as:

Answer 13

3D activation map

Question 14

What colour does higher oxygen consumption show up on the activation map as:

Answer 14

yellow / red

Question 15

Strength Of fMRI: safer than some other scans.

Answer 15

Avoids the use of radiation (unlike PET), therefore is virtually risk free.
Moreover: it is non invasive and as it is virtually risk free - can be used more frequently while still providing a clear image of where brain activity is based
Increase validity

Question 16

Strength Of fMRI: has high spatial resolution.

Answer 16

Since fMRI measures where changes in oxygenated blood flow happen - very good at identifying the exact source (location) of neural activity unlike techniques like EEG.
Typical scans can distinguish between activity of brain regions 3mm apart, however some high-resolution scans like fMRI can achieve this at a resolution of less than 1mm.

Question 17

Strength Of fMRI: it provides both functional and structural info.

Answer 17

Helps us understand change in brain activity during tasks compared to PMA which only gives info on structure of the brain.
Moreover fMRI can measure deeper regions of the brain, e.g, amygdala, compared to EEG/ERP which measures areas near the surface only.

Question 18

Weakness Of fMRI: poor temporal resolution compared to EEG.

Answer 18

As fMRI measures changes in blood flow - it is much slower than changes in neural activity and lags behind neural activity by several seconds - can make interpreting changes in activity caused by an event difficult.
Furthermore, quick changes in activity of brain (e.g ones that last 50ms) will not be detected/ differentiated well by fMRI.
Therefore, not effective technique for identifying when neural activity happens.

Question 19

Weakness Of fMRI: expensive which leads to reduced sample sizes compared to EEG.

Answer 19

Bc of the reduced sample sizes (approx less than 25 ppts) - limits generalisability of the sample
Moreover, its expensive nature reduces accessibility to many researchers, making it inaccessible.

Question 20

Electroencephalogram (EEG):

Answer 20

EEG MEASURES ELECTRICAL ACTIVITY IN THE BRAIN.
- This involves electrodes being placed on the scalp which detect small electrical charges resulting from neural activity occurring in brain cells.
- The number of electrodes planted are based on the areas of research.
Wider area = more electrodes
- These electrodes record signals from thousands of neurons directly under the electrodes - provides a measure of general activity of the brain
- Four patterns of electrical activity that EEG picks up on is: alpha, beta, delta and theta waves

Question 21

Four patterns of electrical activity that EEG picks up on is:

Answer 21

alpha, beta, delta and theta waves

Question 22

Strength Of EEG: has helped diagnose and research disorders.

Answer 22

EEG has allowed us to better understand brain activity that involves random bursts of electrical activity - helped develop an understanding of epilepsy + assist its diagnosis.
Moreover, EEG has helped further our understanding on sleep cycles by showing there are different brain waves in different stages of sleep.
Increases validity.

Question 23

Strength Of EEG: high temporal resolution.

Answer 23

Unlike fMRI which has a delay between neural activity and blood flow- EEG has no delay between electrical currents and neural activity. EEG picks up quick changes in neural activity which happen each millisecond. Bc it has high temporal resolution - EEGs can help identify exactly when neural activity occurs

Question 24

Strength Of EEG: cheaper than fMRI.

Answer 24

Leads to larger sample size + more affordable - increases generalisability of findings of studies where EEG was used. Makes EEG a more accessible method to researchers.

Question 25

Weakness Of EEG: low spatial resolution.

Answer 25

This is bc EEG measures the combined activity of many neurons in diff parts of the brain underneath the electrodes. Therefore, EEG signals are not useful for pinpointing the exact source of neural activity and need methods like fMRI to do this.

Question 26

Weakness Of EEG: cannot detect deeper activity.

Answer 26

Only detects activity under the surface of the electrodes. Activity in deeper regions like amygdala may not be picked up. Thus, does not provide a complete picture of the brain’s functions and activity

Question 27

Event related potential (ERP):

Answer 27

• In ERP, electrodes are placed on the scalp to detect neuronal activity (directly below area of placement) and measure changes in voltage and uses the same equipment ad EEG.
• This is measured while being shown a specific stimulus repeatedly while measuring brain activity.
• It requires repeated presentation of the stimulus which leads to recurring electric voltage activity which is then statistically averaged together.
• This helps to remove (negates) the effect of extraneous activity that is unrelated to the stimulus. This helps isolate the electrical activity triggered by the stimulus.
• This activity we call ERP
• (provides functional and not structural info)

Question 28

Strength Of ERP: it uses EEG technology which has good temporal resolution.

Answer 28

Unlike fMRI which has a delay between neural activity and blood flow- ERP has no delay between electrical currents and neural activity. ERP picks up quick changes in neural activity which happen each millisecond. Bc it has high temporal resolution - ERP can help identify exactly when neural activity occurs

Question 29

Strength Of ERP: it uses EEG technology which is cheap compared to fMRI.

Answer 29

Leads to larger sample size + more affordable - increases generalisability of findings of studies where ERP was used. Makes ERP a more accessible method to researchers.

Question 30

Weakness Of ERP: conducting it is time consuming.

Answer 30

As ERPs are small and difficult to pick out from other brain electrical activity, it thus requires large number of trials which are needed to gain meaningful data and be able to eliminate extraneous activity. This is time consuming and therefore not ideal for all research situations, e.g. testing young children as they struggle to concentrate for long periods.

Question 31

Weakness of ERP: uses EEG technology which has low spatial resolution.

Answer 31

This is bc ERP measures the combined activity of many neurons in diff parts of the brain underneath the electrodes. Therefore, ERP signals are not useful for pinpointing the exact source of neural activity and need methods like fMRI to do this.

Question 32

DIfference between EEG and ERP:

Answer 32

EEG looks at GENERAL changes in brain activity OVER TIME (during STATES such as sleep) whereas ERP measures SPECIFIC brain activity that occurs in response to PRESENTATION of a SPECIFIC STIMULUS, e.g. a face.