Studying the brain

• What is a Post-Mortem Examination?

  - Way of examining brain after one's passing to establish neurological cause for psychological abnormalities

  - Broca's work with 'Tan' is an example of when this had been used

  - Made it possible to identify brain structures involved in memory e.g. HM case study linked to lesions in hippocampus

  - Been used to establish link between disorders e.g. schizophrenia and depression and brain abnormalities
• Evaluate Post-Mortem Examinations


  ✓ Allow for detailed anatomical and neurochemical aspects of brain

  ✗ Can't gain full consent

  ✗ Brain activity dies
• What is Functional Magnetic Resonance Imaging (fMRI)?

  - Technique for measuring brain activity by detecting blood flow (increased oxygenation) indicating increased neural activity

  - Maps produced showing areas of brain active during particular activity
• Evaluate fMRI


  ✓ Noninvasive, no insertion of instruments/exposure to radiation

  ✓Objective and reliable measure of psychological processes

  ✗ Not direct measure of neural activity
• What is Electroencephalogram (EEG)?


  - Records changes in electrical activity of brain using electrodes attached to scalp

  - Electrical signals from diff electrodes graphed over time

  - 4 basic patterns:

  ○ alpha waves - awake but relaxed

  ○ beta waves - physiologically aroused and REM sleep

  ○ delta waves - during sleep

  ○ theta waves - during sleep
• Evaluate EEG


  ✓ Provides recording of brain's activity in real time, accurately measure particular tasks

  ✓ Useful in clinical diagnosis e.g. epileptic seizures

  ✗ Only detects activity in superficial regions, doesn't reveal what occurs in deeper regions

  ✗ EEG signal not useful in pinpointing exact source of activity, can't always distinguish between activities originating in diff. but close locations
• What are Event-Related Potentials (ERPs)?

  - Similar to an EEG

  - Very small voltage changes triggered by certain events/stimuli detected

  - Requires many presentations of stimulus and responses to be averaged to remove any extraneous neural activity
• Evaluate ERPs


  ✓ Measure processing of stimuli in absence of behavioural response

  ✗ Small and difficult to pick out, requires large number of trials to gain meaningful data

  ✗ Only sufficiently strong voltage changes are recordable, those occurring deep in the brain may not be recorded making it restricted