Ways of studying the brain

Question 1

What are the 4 main ways of studying the brain?

Answer 1

• Functional magentic resonance imaging (fMRI)
• Electroencephalogram (EEG)
• Event-related potentials (ERP)
• Post-mortem examinations

Question 2

What is the purpose of scanning techniques?

Answer 2

To investigate localisation

Question 3

What are fMRIs?

Answer 3

Method to measure brain activity while a person performs a task

Question 4

How do fMRIs work?

Answer 4

• Detects change in blood flow and oxygenation occuring as a result of neural activity in specific parts of the brain
• Active brain areas consume more oxygen to meet increased demand so blood flow directed to active area (harmodynamic response)
• Produces 3D images (activation maps) showing which parts of the brain are involved in particular mental processes

Question 5

What are EEGs?

Answer 5

Record of tiny electrical impulses produced by the brain’s activity

Question 6

How do EEGs work?

Answer 6

• Measures electrical activity in the brain via electrodes (fixed to the scalp using a skull cap)
• Scan recordings represent brainwave patterns generated from thousands of neuron actions

Question 7

What are EEGs used for?

Answer 7

Used by clinicians as a diagnostic tool: unusual arrythmic patterns of activity may indicate neurological abnormality (epilepsy)

Question 8

What are ERPs?

Answer 8

The electrophysiological responses of the brain to a specific sensory, cognitive or motor event, can be isolated through statistical analysis of EEG data

Question 9

How do ERPs work?

Answer 9

• Neural responses which are associated with sensory, cognitive and motor events, are contained within ERP data
• Use of statistical avergaing techniques allow extraneous brain activity from EEG recordings to be filtered out, leaving only responses relating to presentation of a specific stimulus/performance of a specific task

Question 10

What are post-mortem examinations?

Answer 10

Analysis of the brain after death to determine whether certain observed behaviours during a person’s lifetime can be linked to structural abnormalities in the brain

Question 11

How do post-mortem examinations work?

Answer 11

• Analyses the brain after death
• Individuals who receive post mortems often have rare disorders or unusual cognitive deficits
• Areas of damage are analysed, establishing cause of affliction
• May involve comparison with neurotypical brain to ascertain extent of the difference

Question 12

Strengths of fMRIs

Answer 12

• Doesn’t rely on use of radiation- so virtually risk-free, non-invasive and straightforward
• Images produced have very high spatial resolution- detail by mm- provides clear picture of localisation and brain activity

Question 13

Limitations of fMRIs

Answer 13

• Expensive
• Poor temporal resolution- 5 second lag behind image on screen and firing of neural activity- does not fully represent of moment to moment activity

Question 14

Strengths of EEGs

Answer 14

• Useful in studying sleep stages and epilepsy diagnoses (detected by random bursts of energy on screen)
• Extremely high temporal resolution- detects brain activity at resolution of one millisecond
• Real world value

Question 15

Limitations of EEGs

Answer 15

• Information received has been generalised (that of many thousands of neurons)
• EEG signal is not useful for pinpointing the extact source of neural activity- poor spatial resolution- does not distinguishing between activities originating in different but adjacent locations

Question 16

Strengths of ERPs

Answer 16

• Addresses EEG limitations - i.e. more specificity to measurement of neural processes
• Excellent temporal resolution- so useful to measure cognitive functions and deficits (i.e. maintenance of wmm)

Question 17

Limitations of ERPs

Answer 17

• Lack of standardisarion between research studies- difficult to confirm findings
• Impure data- extraneous material has not been eliminated (background noise)

Question 18

Strengths of post mortems

Answer 18

• Provides foundation for early understanding of key brain processes- Broca and Wernicke used post mortems to establish links between language, brain and behaviour
• Used to study HM’s brain to identify damaged areas associated with memory deficits- provide useful information

Question 19

Limitations of post mortems

Answer 19

• Does not explain causation- observed damage to brain not linked to deficits under review, but to unrelated trauma/decay
• Raises ethical issues of informed consent prior to death (e.g: HM lost memory)