ways of investigating the brain

• fMRI (functional magnetic resonance imaging)


  MRI whilst doing a task. Measures blood flow to active parts of the brain, magnet picks up iron in the blood. USES: Get people to speak & see if Broca's area lights up; provide evidence for localisation of function. Get people to watch porn to see if they're addicted. Can use whilst doing scalpel-free surgery.
• EEG (electroencephalogram)


  Electrons/electrode cap placed on scalp; measures brain wave activity underneath it. Picks up the action potentials from millions of neurones under each electrode. Non-invasive. USES: Discover abnormal sleep patterns, Good way to detect epilepsy & Alzheimer's
• ERPs (event related potentials)


  EEG with a task, Uses electrode cap, More precise measurement as it filters out extraneous brainwave information & only records brain waves relating to the event. USES: Detect Parkinson's, dementia, Used in child development psychology & neuromarketing
• Post mortem examination


  Brain is analysed after death, Can compare normal brain with abnormal brain. USES: Broca used post mortem to identify cause of Tan not being able to produce normal speech & found damage to frontal lobe: Broca's areas, However unsure from post mortem about cause & effect, Helps us to determine the extent & localisation of brain disease
• fMRI positives

  Provides clear picture about how activity is localised, shows dynamic information as it involves the person doing a physical or mental task, Measures blood flow due to iron in blood, doesn't use radiation so is risk free for patients in comparison to X-rays & is non-invasive, however can't be used on people with pacemakers or metal implants-Produces images which have good spatial resolution
• fMRI negatives


  Can only measure blood flow in the brain, not electrical brainwave activity so can't hone in on activity of individual neurons, Expensive technique so may no be able to use in research/ may lead to small sample sizes so might be be representative & therefore can't generalise, Low temporal resolution: complex reading
• EEG positives


  Measures electrical brain wave activity, provides valuable data to help diagnose conditions such as epilepsy, Non-invasive - doesn't use radiation so risk-free, Less expensive than using fMRI's so used more in research & can increase sample size.
• EEG negatives

  Unable to detect activity deeper in the brain, Poor spatial resolution - difficult to pinpoint exact area/region of activity, Uncomfortable for ppts as electrodes are attached to the scalp - could result in unrepresentative readings.
• ERPs positives


  Measures electrical brain wave activity via electrodes providing valuable data to help diagnose conditions, Non-invasive - don't use radiation so risk-free, less expensive than fMRIs so used more in research & can increase sample size, good temporal validity - can record change on a millisecond level.
• ERPs negatives


  Unable to detect activity deeper in the brain, poor spatial resolution - electrical activity is detected in several regions at once making it difficult to pinpoint the exact region of activity, Electrodes can be uncomfortable - could result in unrepresentative readings.
• Post-mortem examination positives 


  Detailed spatial resolution - brain is cut into thin sections & can be digitised, Not as expensive as fMRI, Provide a detailed examination of the anatomical structure & neurochemical aspects of the brain, Can look at the whole brain closely & in detail.
• Post mortem examinations negatives

  Can't measure active blood flow as person is dead, Can't measure brain activity as person is dead, No temporal validity, Takes time to do, Unsure of causation as the structure that is abnormal may not be the cause of the behaviour/issues being examined - unsure if changes are a result of neuronal changes after death, Sample size issues - may be difficult to get people to agree to their brain being used in research, Ethical issues of consent - may be carried out on patients with severe psychological deficits.