Ways of studying the brain

• What are the weaknesses of post mortem dissections as a method of investigating the brain?

  no brain activity can be measured.

  
  

  The brain could have been affected by the cause of death.

  
  

  Any relationship found would be a correlation as no experiments can be done.
• What are the strengths of post mortem dissections as a method of investigating the brain?

  fundamental in understanding how brains function e.g. this was how Broca's area was discovered.

  
  

  Individual is not alive so cannot experience discomfort or pain.
• How do post mortem dissections work?

  when a persons brain is examined after death, specifically people who have suffered from trauma or mental illnesses to compare to healthy brains.
• What are the weaknesses of EEGs as a method of investigating the brain?

  not as accurate as imagine techniques

  
  

  Expertise is needed to translate the outcome

  
  

  Unable to detect deep brain activity
• What are the strengths of EEGs as a method of investigating the brain?

  cheaper alternatives to imagine techniques

  
  

  Help to test reliability on self report techniques

  
  

  Practical applications in sleep and medical diagnosis

  
  

  Allows researchers to isolate individual cognitive processes in the brain.
• Describe how EEGs work.

  around 22-34 electrodes fitted to a cap are placed on. Patients head where they measure the activity directly underneath. The activity is displayed in brain waves in which the amplitude shows intensity and frequency shows the speed of activation.
• What are the weaknesses of FMRIs as a method of investigating the brain?

  expensive to build and maintain.

  
  

  Patient needs to remain extremely still which could become difficult with children or people with disabilities.

  
  

  Due to availability and expenses, the sample size is often very small.
• What are the strengths of FMRIs as a method of investigating the brain?

  non evasive and safe.

  
  

  Produces a moving picture so comparison over time can be made.

  
  

  Spacial resolution of 1mm means brain regions can be accurately identified.
• Describe how FMRIs work.

  They are similar to MRIs however instead of measuring energy emitted from water, it measures the energy released from from oxyhaemoglobin. It work by detecting oxygenated haemoglobin in the blood through large magnets. The oxygenated blood shows where the brain is more active, and deoxygenated blood less active.
• Describe some imaging techniques for brain scans.

  Cat scan - X-ray beams are used to produce a picture of the brain.

  
  

  Pet scan - injecting the patient with a radioactive isoptopes that react with glucose or water to form radiotracers to produce a picture of the brain.

  
  

  MRIs - records energy produced by molecules of water in the brain.
• What are the three techniques for research into the brain?

  Imaging techniques, EEGs, and post mortem dissections.
• Which methods are used to study the brain?

  fMRI, EEG, ERP and Post-mortems
• Which method is invasive

  Post-mortems
• Which methods are not invasive

  EEG, ERP and fMRI
• What does fMRI stand for and how does it work?

  Functional magnetic resonance imaging

  Uses a magnetic field and radio signals to measure the blood flow in the brain

  The patient lies in a large metal tunnel surrounded by a large magnet

  When an area of the body is exposed to a radio-frequency pulse, the tissues in the body give out a signal that is measured

  fMRI detects energy released by the haemoglobin and produces a moving picture
• Strengths of fMRI

  A moving picture of the brain means activity can be compared rather than just physiology

  Good for diagnosing brain and spinal cord diseases
• Weaknesses of fMRI

  Machines are expensive so they can be challenging to purchase and maintain

  The scans are complex so they can be difficult to interpret
• EEG

  Electrodes are placed on the head and the electrical signals from the neurons firing are represented on a screen
• ERP

  Similar to an EEG, but measures the response to a stimulus given by the researcher
• Strengths of ERP and EEG

  Cheaper methods = more widely available

  Can test the validity of self report methods

  Good for research into sleep and epilepsy
• Weaknesses of ERP and EEG

  Results need to be interpreted to expertise is required

  Finer details can be missed as both methods only measure activity close to the electrode
• Advantages of Post-mortem


  No discomfort for the patient as they're not alive
• Disadvantages of Post-mortem

  No brain activity measured

  Issues with comparing to functions prior to death

  The brain may have been tainted by the reason for death e.g. disease