Studying the brain

• Invasive studying of the brain - cutting open the skin and going inside the brain
• Non invasive studying of the brain - do not cut into the brain
• Post mortems - invasive - dissecting and examining the brain of deceased patients, looking for evidence of brain abnormality. This can be related back to abnormal behaviours the patient displayed in life
• MRI - Non invasive - Magnetic Resonance Imaging

  Generates an image of the inside of a persons brain

  Show the structure of the brain, but not brain activity
• fMRI - non invasive - Functional Magnetic Resonance Imaging

  Uses standard MRI to generate an image of the brain, while also measuring changes in brain activity

  Does this by measuring the changes in blood flow in parts of the brain while people perform tasks
• EEG - Non invasive - electroencephalogy

  Measures neural activity in the brain using electrodes placed on the scalp that measure electrical activity from groups of neurones
• ERPs - non invasive - Event Related Potentials

  Small electrical signals the brain produces in response to stimulus

  Measured by presenting the same stimulus across hundreds of trials, recording EEGs on each trial, which are averaged to identify ERPs, which can be related back to the stimulus
• Invasive methods of studying the brain: 

  Post mortem 
• Non invasive methods of studying the brain: 

  MRI 

  fMRI 

  EEG

  ERPs
• Post mortem evaluations:

  ☑ Allows the brain to be examined in high detail and identify small abnormalities

  ☒ It can be difficult to establish a cause and effect relationship between the patient's abnormal behaviour and brain abnormality

  ☒ Difficult to control confounding or extraneous variables like medication
• fMRI Evaluations:

  ☑ Researchers can look at brain activity while people are behaving, meaning we can look closely at the relationship between brain activity and behaviour

  ☒ Difficult to establish cause and effect relationship, just because a region is active it doesn't mean its responsible

  ☒ Blood flow is an indirect measure of neural activity and is not completely related `
• EEG Evaluation:

  ☑ Can directly measure neural activity generated by neurones in the cortex, rather than relying on indirect measures

  ☑ Good at detecting synchronised activity that occurs when people sleep or when they have seizures

  ☒ We don't know which neurons are generating the activity

  ☒ Only detects neural activity from the cortex
• ERPs evaluation:

  ☑ Can identify small electrical signals associated with a specific stimulus event

  ☒ We can't tell which neurons generated the signal

  ☒ We can only look at signals generated by the cortex

  ☒ ERPs can be impractical, as we require a huge number of trials to obtain meaningful data
• Spatial resolution - level of detail the methods allow us to examine the brain
• Spatial resolution rankings:

  1 - Post mortem

  2 - fMRI

  3 - EEGs + ERPs
• Temporal resolution - precision of our measurements with respect to time
• Temporal resolution rankings:

  1 - EEGs + ERPs

  2 - fMRI

  Post mortems have no temporal resolution