ways of studying the brain

• What does fMRI measure?

  Blood flow in the brain when a person performs a task
• What is the idea that fMRI is based on?

  That neurons in the brain which are the most active (during a task), use the most energy
• How does fMRI measure blood flow?

  fMRI use magnetic field and radio waves to detect changes in blood oxygenation and flow as a result of neural activity
• What image does fMRI create?

  A dynamic 3D image of the brain
• What can fMRI be used to do?

  Activity in regions of interest can be compared between a specific activity and a baseline task
• Is fMRI invasive or not? Justify your answer

  Non-invasive

  
  

  Does not use radiation or involve inserting instruments directly into the brain
• What is the spatial resolution of fMRI? Justify your answer.

  Good

  
  

  Approximately 1-2 mm which is significantly greater than other techniques
• What is the temporal resolution of fMRI? Justify your answer.

  Poor

  
  

  1-4 seconds which is worse than other techniques
• What is the cost of fMRI?

  Very expensive

  
  

  Scanner costs around £100k - £200k
• What does EEG measure?

  Electrical activity in the brain (brain waves)
• How does EEG measure electrical activity?

  Via electrodes that are fixed to the individuals scalp
• How is the EEG graph created?

  Small electrical charges that are detected by the electrodes are graphed over a period of time, indicating the level of activity in the brain. The scan records brainwave patterns
• What can EEG be used to do?

  Often used by clinicians to identify unusual patterns of activity that may indicate neurological abnormalities, such as epilepsy, tumours or disorders of sleep
• Is EEG invasive or not? Justify your answer

  Non-invasive

  
  

  Does not use radiation or involve inserting instruments directly into the brain
• What is the spatial resolution of EEG? Justify your answer.

  Poor

  
  

  Only detect the activity in superficial regions of the brain
• What is the temporal resolution of EEG? Justify your answer.

  Good

  
  

  Takes readings every millisecond
• What is the cost of EEG?

  Cheap

  
  

  Scanner costs around £13k
• What do ERPs measure?

  Very small voltage changes in the brain that are triggered by specific stimuli
• How are ERPs measured?

  Using EEG equipment
• What happens during researching measuring ERPs?

  A stimulus is presented and the researcher looks for electrical activity related to that stimulus.
• What needs to happen with ERP data and why?

  As ERPs are difficult to separate from all of the background EEG data, the stimulus is present hundreds of times, and an average response is graphed.
• What is the control method we use with ERPs called and what does it do?

  This procedure, called 'averaging', reduces extraneous neural activity which makes the specific response to the stimulus stand out.
• What is the time between stimulus and response is referred to as?

  Latency
• What is the latency for ERPs?


  ERPs have a very short latency and can be divided into two broad categories.
• What are the two categories of ERP latency?

  Within 100 milliseconds and after a 100 milliseconds
• What are waves that occur within 100 milliseconds?

  Sensory, as they reflect a sensory response to the stimulus
• What are waves that occur after 100 milliseconds?

  Cognitive, as they demonstrate some information processing
• Are ERPs invasive or not? Justify your answer

  Non-invasive

  
  

  Does not use radiation or involve inserting instruments directly into the brain
• What is the spatial resolution of ERPs? Justify your answer.

  Poor

  
  

  Only detect the activity in superficial regions of the brain
• What is the temporal resolution of ERPs? Justify your answer.

  Good

  
  

  Takes readings every millisecond
• What is the cost of ERPs?

  Cheap

  
  

  Scanner costs around £13k
• What is a post-mortem?


  The analysis of the brain after someone has died
• Who is studied using post-mortems?

  Individuals whose brains are studied tend to have rare illnesses or defects that can be studied
• What happens during a post-mortem?

  Areas are examined after death to try and identify the possible causes of the affliction the person suffered from
• What can post-mortems be used to do?

  Compare the brain to an unaffected brain to see the differences
• Are post-mortems invasive or not? Justify your answer

  Invasive

  
  

  This is not an issue because the patient is dead but raises ethical issues in relation to informed consent and whether a patient provides consent before their death
• What is a strength of post-mortems?

  They provide a detailed examination of the anatomical structure and neurochemical aspects of the brain that is not possible with other scanning techniques
• What are deep areas of the brain that can be studied using post-mortems?

  Hypothalamus and hippocampus
• What is a main limitation of post-mortems?

  Issue of causation
• What issue is there with causation and post-mortems?

  The deficit a patient displays during their lifetime may not be linked to the deficits found in the brain