brain scans and procedures

fMRI

• Creates moving picture which allows for comparison

• Difficult to interpret fMRI due to complexity of brain and time delay of scan

• Expensive to buy and maintain, requires trained operators so research is difficult to organise

• Sample studies often small due to limited availability and funding, leads to little generalisability

CT, PET and MRI

CT — computed tomography

• Uses x ray beam to produce picture of brain’s physiology

• Not moving but identifies damage/lesions and usual activity

PET — positron emission tomography

• Creates moving picture using radioactive glucose injected in bloodstream

• Most active areas use most glucose

MRI — magnetic resonance imaging

• Same as fMRI but not moving pictures (using molecules of water)

EEG

• 2-3 to over 100 electrodes placed in scalp (measures activity directly under cells, so more is better for fuller picture)

• Dement and Kleitman — identified brain waves during sleep

ERP

• Same apparatus as EEG but using stimuli to compare to their normal waves

• Costa et al — males admit arousal at nude female pictures, females claimed not, ERP showed that both genders aroused by opposite sex so ERPs are more accurate than self reports

• Evaluation:

  • Accurate for activity close to electrodes but finer details are missed and only suitable for certain research

  • EEGs and ERPs are cheaper than scanning

  • Output from equipment needs interpreting by an expert

  • ERPs are useful for the reliability of self reports, supplementary method for research, especially if sensitive topics or open to social desirability bias

post mortem examinations

• Brain examined after death to observe damage that might have occurred to cause behaviours

• Domanski — report on Broca finding Broca’s area via post mortem

• Iversen — found schizophrenic patients have excess dopamine in limbic systems

• Reeves and plum — found obese female had destroyed ventromedial hypothalamus, neural factors could be involved in obesity