Ways of studying brain

• fMRI


  Measures brain activity.

  Detects change in blood flow and blood oxygenation in response to neural activity.

  Based on assumption that more active brain is, more oxygen needs, so there'll be more blood going to active areas.
• fMRI


  Used to produce activation maps to show which areas of brain involved in specific mental processes.

  Allows us to study localisation of mental processes.
• fMRI - Advantages


  Easy to use

  No radiation - no harm to subject

  Non-invasive

  High spatial resolution so can see very small areas clearly
• fMRI - Disadvantages


  Expensive

  Low temporal resolution - 1-4 sec

  Data has to be interpreted by researcher

  Data undergoes thorough statistical analysis, incl thousands of comparisons, so some likely to turn out positive, even if wrong - false positives

  Corrections must be made but cud lead to false negatives
• fMRI - Bennet (Disadvantage)


  Did spoof experiment on ded salmon.

  Found that using standard technique showed brain activity in ded salmon.
• EEG


  Records brain activity.

  During test, small sensors pick up electrical signals when brain cells message each other.

  Signals recorded by machine.
• Electrodes cant pick up signals from individual neurons.
• EEG used to show either presence/absence of specific brain activity in specific area of brain.
• EEG - Advantages


  Easy to use

  Cheap

  Only one that shows abnormalities of epileptic patients.

  Direct evidence.

  Often used to supplement neuroimaging e.g. MRI.
• EEG - Disadvantages


  Low specificity and sensitivity - cant see functioning of small areas of brain.

  Influenced of drugs and state of alertness.

  Only show neural activity in cortex, not small or deep lesions.
• ERP


  Brain response that results from sensory, motor, cognitive event.
• ERP


  Person connected to EEG machine and presented with various stimuli.

  Resulting EEG trace analysed.

  First trace needs to be filtered in order to detect any changes in types of neural activity.
• ERP - Advantages


  High temporal resolution - within 1 millisecond

  used in study of cognitive functions
• ERP - Disadvantages


  Lack of standardisation in ERP research means difficult to compare results of diff studies.

  EEG picks up all neurological activity so extraneous variables and background noise need to be removed, which is difficult and time - consuming to do.
• Post mortem


  study of persons brain after death.
• Post mortem


  Used to study link between structure and function of brain.

  e.g. Brocca found damage to small area in frontal part of left hemisphere led to difficulty producing speech.
• Post mortem


  Today used to study abnormalities associated with disorders e.g. Alzheimer's and motor neurone disease.

  People with these disorders, their brain compared to normal brains and correlation made between differences an disorder.
• Post Mortem - Disadvantages


  Difficult to obtain consent from patient's family.

  Lesions cud be due to other processes/factors during patients life, not disorder studying.

  State of brain influenced by cause of death and method of storage after death - confounding variables.
• Post Mortem - Advantages


  Allow researchers to gain info about processes involved in specific disorders.

  Lead to improvement in treatment for patients with disorder.

  Lead to prevention for disorder for others.

  Allow researchers to prioritise areas of study.