Bio psych- ways of studying the brain

Question 1

What is a post-mortem examination

Answer 1

When a person’s brain is examined after they have died

Question 2

What happens during a post mortem examination

Answer 2

The brain is sliced into thin sections and studied on a microscope to detects abnormalites

Question 3

Strengths of Post mortem examinations

Answer 3

Allow detailed examination of the anatomical aspects of the brain that is not possible with non-invasive techniques. E.g. HMs brain was examined to identify the role of the hippocampus in memoryHarrison (2000) suggested that structural and neurochemical abnormalities linked to schizophrenia were first identified using this method, which led to greater understanding

Question 4

Weaknesses of post mortem examinations

Answer 4

Retrospective method so it may be hard to make comparisons with functioning before death, so creating clear cause and effect r/ships is trickyAs soon as oxygen is cut off from the brain the shape and structure of many parts so findings may lack accuracy, and questions the usefulness of he method

Question 5

How do fMRIs work

Answer 5

by using strong magnetic and radio waves to monitor blood flow and blood oxygenation in specific parts of the brain.

Question 6

What do fMRIs measure

Answer 6

Blood flow and blood oxygenation Areas of high activity will show correspondingly high levels of blood oxygenation and blood flow

Question 7

Strengths of an fMRI

Answer 7

Provides a moving picture of brain activity rather than just the bland static pictures. The high spatial resolution, detailing each millimeter of the brain is highly valuable when trying to link brain activity to key behaviours.It is non-invasive and does not expose the brain to potentially harmful radiation as can be found in PET scans. Hence, it is quite an ethical method.

Question 8

Weaknesses of fMRIs

Answer 8

The complexity of brain activity means interpreting the scan is quite complex and problematic. Although fairly objective - it needs a highly trained eyeIt has poor temporal resolution - due to a 5 second time-lag (5 second delay b/w image on screen and neuronal activity). Hence, not truly moment-to-moment brain activity

Question 9

How do EEGs work

Answer 9

Small sensors (electrodes) are attached to the scalp to pick up the electrical signals produced by thousands of brain cells communicating

Question 10

What do EEGs measure

Answer 10

The amplitude (size) and frequency of the electrical activity in the brain and identifies patterns in activity that may be associated with certain states (e.g. sleep). This means it can help to identify abnormalities in any of these areas.

Question 11

Strengths of EEGs

Answer 11

Can be used effectively in clinical practice to identify stages of sleep & sleep disorders (i.e. identify disturbed brain activity and help with diagnosis) and diagnosing epilepsy (inconsistent brain activity) This is cheaper than many other methods of studying the brain so is used more extensively. High temporal resolution (unlike fMRI) - so can give moment-by-moment glimpses of brain activity

Question 12

Weaknesses of EEGs

Answer 12

The output from the machines needs to be interpreted and a high level of expertise is required to use this method effectively. Poor spatial resolutionElectrical activity can be picked up by several neighbouring electrodes therefore the signal is not useful for pinpointing the exact source of activity and is only useful for showing general activity levels.

Question 13

How does an ERP work

Answer 13

ERPs use a similar array of recording electrodes as an EEGThey take recordings from numerous presentations and then average out the responses to obtain an event-related potential

Question 14

What do ERPs measure

Answer 14

electrical activity in response to a specific stimulus.

Question 15

Weaknesses of ERPs

Answer 15

The output from the machines needs to be interpreted and a high level of expertise is required to use this method effectively. Poor spatial resolution = 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 - unlike fMRI scans

Question 16

Strengths of ERPs

Answer 16

Useful to measure the 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.High temporal validity It can directly measure neuronal activity and give the earliest indication of conscious cognitive processing. This is because it can detect the slightest changes due to any environmental manipulation of stimuli (high temporal resolution)