ways of studying the brain

• fMRI

  Detects blood flow in the brain.

  As more active areas of the brain need more blood, these active areas can be compared to low activation areas with a lower blood supply and displayed on a fMRI image.
• EEG

  Measures electrical activity within the brain via electrodes that are fixed to the scalp. Brainwaves are recorded. Size of the waves (amplitude) show brain wave intensity, frequency (distance between each wave) shows the speed of activation.
• ERP (Event-related potentials)


  Uses the same equipment as EEG, but presents a stimulus many times, creating a smooth curve of activation by combing the data in a process called statistical averaging. This removes background electrical noise unrelated to the stimulus.
• Post-mortem examinations

  The brain is analysed after death to determine whether certain observed behaviours during the patient's lifetime can be linked to abnormalities in the brain. They are compared with healthy brains.
• + fMRI

  • Good spatial resolution - the spatial resolution is approximately 1mm. This precisely identifies active brain regions and patterns of activation over time while participants complete experimental conditions.
  • fMRI is non-invasive and safe technique for experiments compared to options that use radiation like PET scanners.
• / fMRI

  • Poor temporal resolution - as one image is taken every few seconds and delay in blood flow after activity. Many brain processes are too fast to study.
  • fMRI machines are expensive to build and operate. Also the participant needs to be still, experiments with body movement are not possible.
• + EEG

  • Historically important in understanding brain activity in areas such as sleep research and medical diagnosis.
  • Cheaper than alternatives such as fMRI and able to be used in experiments where the participant moves.
  • Good temporal accuracy, measuring brain activation with a resolution measured in milliseconds.
• / EEG

  • Poor spatial activity as pattern is sum of a large number of neurons in the cortex under the electrode. Also cannot detect activity deep within the brain.
• + ERP

  • Allow researchers to isolate and study how individual cognitive processes take place in the brain, while EEG's record general brain activity.
  • ERP's have good temporal resolution with a millisecond sampling rate.
• / ERPs

  • ERPs have very poor spatial resolution.
  • Some processes cannot be studied by ERP as they cannot be presented a large number of times with the same response.
• + Post-mortem examination

  • High spatial resolution of post mortem allows the study of microscopic brain structures down to the neuronal level.
  • Theories can be generated that can be tested with other experimental techniques.
• / Post-mortem examinations

  • As post mortem is not conducted on the living brain, unusual behaviour in life and damage found is correlational.