4 Ways of Studying the Brain

Question 1

What are the four ways of studying the brain?

Answer 1

• Postmortem examinations
• fMRI (functional magnetic resonance imagery)
• EEG (electroencephalogram)
• ERP (event-related potentials)

Question 2

What is a post mortem examination?

Answer 2

When examinations take place ‘after death’ on the brain, you can see where damage occurred and how behavior prior to death may have happened. The brain can be sliced and studied under a microscope.

Question 3

Advantages of post mortem examination?

Answer 3

1. Detailed examination of anatomical aspects that is not possible with non invasive techniques
2. Harrison (2000) suggested that structural and neurochemical abnormalities linked with schizophrenia were first identified by using this method

Question 4

Disadvantages of post mortem examinations?

Answer 4

1. Retrospective method so it may be hard to make comparisons with functioning brain before death
2. As soon as there is no O2 the brains shape and structure of many parts may lack accuracy

Question 5

What is Functional Magnetic Resonance Imagery (fMRI)?

Answer 5

Strong magnetic and radio waves monitor blood flow in the brain, takes repeated scans to create an image of the concentration of oxygen in the blood at any given time, areas of high activity will show corresponding high levels of blood oxygenation and flow, sections of the brain that are more active during certain tasks can be identified.

Question 6

What is the temporal resolution of fMRI?

Answer 6

Poor temporal resolution (1-4 seconds).

Question 7

What is the spatial resolution of fMRI?

Answer 7

Good spatial resolution (1-2mm)

Question 8

Advantages of fMRI?

Answer 8

1. Provides a moving image of activity rather than just the physiology of the brain so can link activity to tasks or behavior
2. Non-invasive and doesn’t expose the brain to harmful radiation

Question 9

Disadvantages of fMRI?

Answer 9

1. The complexity of brain activity means interpreting scan is complex and problematic
2. Focuses only on localized activity of the brain so may not identify important ways in which communication between different regions affects mental functioning

Question 10

What is an Electroencephalogram (EEG)

Answer 10

Recording of brain activity, small sensors are attached to the scalp to pick up electrical signals produced when brain cells send messages to one and other. Measures the amplitude and frequency of electrical activity, identifying patterns in activity associated in certain states during sleep. Can detect and investigate epilepsy.

Question 11

What is the spatial resolution of an EEG?

Answer 11

Poor spatial resolution (superficial general regions).

Question 12

What is the temporal resolution of an EEG?

Answer 12

Very good temporal resolution (1-10ms)

Question 13

Advantages of EEG

Answer 13

1. Used effectively in clinical practice to study sleep disorders, identifies disturbed brain activity and helps diagnosis
2. Cheaper than many other methods of studying the brain so is used extensively as it allows for more participants to be viewed and more data to be collected

Question 14

Disadvantages of EEG

Answer 14

1. Output from machines needs to be interpreted and levels of expertise is required
2. Activity can be picked up by neighboring electrodes so signal may not be useful for pinpointing the exact source of activity and is only useful for showing general activity levels

Question 15

What is an event-related potential (ERPs)?

Answer 15

Recording electrodes of electrical activity in response to a specific stimulus, must take recordings from numerous presentations and average out responses to obtain an event related potential. Often used when investigating fast responses that might not be detected by other investigated techniques e.g., fMRI

Question 16

Advantages of ERPs?

Answer 16

1. Useful in measuring reliability of self-reported techniques especially when the topic being investigated is sensitive and likely to be affected by social desirability bias e.g., drug misuse.
2. Directly measures neuronal activity and gives the earliest indication of conscious cognitive processing because it can detect the slightest changes due to any environmental manipulation of stimuli

Question 17

Disadvantages of ERPs

Answer 17

1. Output from machines needs to be interpreted and levels of expertise is required
2. It only detects strong voltage changes across the scalp. Important electrical activity deep in the brain are not recorded, hence this method is limited to just the neocortex.

Question 18

What is the spatial resolution of an ERP?

Answer 18

Poor spatial resolution (superficial general regions only)

Question 19

What is the temporal resolution of an ERP?

Answer 19

Good temporal resolution (1-10ms)

Question 20

Similarities between fMRIs and EEG?

Answer 20

• Both measure activity of brain to show how different areas correspond to activity
• Both noninvasive
• Risk free

Question 21

Differences between fMRIs and EEG?

Answer 21

• fMRI spatial resolution = 1-2mm
• EEG spatial resolution = superficial general regions
• fMRI temporal resolution = 1-4 seconds
• EEG temporal resolution = 1-10ms

Question 22

Differences between fMRIs and ERPs?

Answer 22

• fMRI spatial resolution = 1-2mm

- ERP = superficial general regions

Question 23

Similarities between fMRIs and ERPs?

Answer 23

• Both non-invasive

Question 24

Similarities between EEG and ERPs?

Answer 24

• Both noninvasive
• Both have a temporal resolution of 1-10ms
• Both have spatial resolution that is superficial general regions only
• Similar equipment

Question 25

Differences between EEG and ERPs?

Answer 25

- ERP = stimulus presented to a participant and the researcher looks for activity related to that stimulus - EEG = no stimulus