Lesson 9 - Studying the Brain

Question 1

Post-Mortem Examinations

Answer 1

• Studying abnormalities in the brain that might explain abnormal behaviour
• Found a link between brain abnormalities and psychiatric disorders
• Evidence = Reduced glial cells in frontal lobe of patients with depression

Question 2

PME Evaluation

Answer 2

• Allow for more detailed examination than would be possible with other methods
  
  • Enabled researchers to examine deeper regions, such as the hippocampus and hypothalamus
• Lacks validity - People die in a variety of circumstances and at varying stages of disease
  
  • Length of time between death and post-mortem and drug treatments can all affect the brain
• Very small sample sizes since consent is required meaning findings cannot be generalised

Question 3

FMRI Scans

Answer 3

• Provides indirect measure of neural activity
• Uses magnetic fields and radio waves to monitor blood flow in the brain
• Measures change in energy released by haemoglobin, reflecting brain activity to give a moving picture of the brain
• Activity can be compared between different regions during a given task

Question 4

FMRI Scans Evaluation

Answer 4

• Captures dynamic brain activity rather than pure physiology of the brain
• Good spatial resolution
• Interpretation of fMRI is complex and is affected by poor temporal resolution, biased interpretation and by the task used
• Expensive therefore leading to smaller sample sizes, which decreases validity

Question 5

Spatial Resolution

Answer 5

Refers to the smallest feature that a measurement can detect

Question 6

Temporal Resolution

Answer 6

Resolution of a measurement with respect to time

Question 7

Electroencephalogram

Answer 7

• Directly measures general neural activity in the brain
• Linked to states such as sleep and arousal
• Electrodes placed on the scalp and detect where they are placed
• Results obtained are extrapolated onto a graph called an EEG pattern
• EEG of epilepsy patients = spiked electrical activity
• EEG of brain injury patients = slowing of electrical activity

Question 8

EEG Evaluation

Answer 8

• Useful in clinical diagnosis, can record the neural activity of epilepsy patients to confirm if they are experiencing seizures
• Cheaper than fMRI so can be used more widely in research
• Poor spatial resolution

Question 9

Event-Related Potentials

Answer 9

• Electrodes placed on scalp and DIRECTLY measure neural activity below where they are placed in response to a specific stimulus introduced by the researcher
• ERPs are difficult to pick out from all the other electrical activity generated within the brain
• To get a good result the target stimulus needs to be presented many times and the results are averaged

Question 10

ERP Evaluation

Answer 10

• ERPs can measure the processing of a stimulus even in the absence of a behavioural response = possible to measure covertly the processing of a stimulus
• Cheaper than fMRI so can be used more widely in research
• Good temporal resolution
• Poor spatial resolution
• Only sufficient strong voltage changes generated across the scalp are recordable, ERPs are restricted to the neocortex, since other electrical activity occurring deeper in the brain is not recorded