Ways of studying the brain

• What is the purpose of post-mortem examinations of the brain?

  To determine if observed behaviors can be linked to brain abnormalities.
• When are post-mortem examinations often conducted?

  When a person has shown unusual behavior in life.
• Name three famous cases associated with post-mortem examinations.

  HM, "Tan," and Phineas Gage.
• What do areas of brain damage (lesions) reveal?

  They reveal the localization of function in the brain.
• Who first demonstrated the localization of function in the brain?

  Paul Broca.
• What condition did Broca's patient "Tan" have?

  Expressive aphasia, where he was unable to produce speech.
• What conclusion did Broca draw from Tan's post-mortem examination?

  That speech production was localized to Broca's area in the left frontal lobe.
• What are the strengths and weaknesses of post-mortem examinations?

  Strengths:

  • Vital for early understanding of brain localization.
  • Helped improve medical knowledge and generate hypotheses.

  
  

  Weaknesses:

  • Cannot assume causation from injuries seen after death.
• What does an electroencephalogram (EEG) measure?

  Electrical activity via electrodes attached to the scalp.
• How does an EEG provide output of brain activity?

  It gives a continuous output of activity at each electrode.

  
• What are the four types of EEG patterns?

  Alpha, beta, theta, and delta waves.

  
• What did Dement and Kleitman (1957) use EEGs to observe?

  The stages of sleep and the association of dreams with REM sleep.

  
• What are the strengths and weaknesses of EEGs?

  Strengths:

  • Invaluable for diagnosing epilepsy.
  • High temporal resolution (single millisecond).
  • Non-invasive technique.

  
  

  Weaknesses:

  • Poor spatial resolution; cannot pinpoint exact neural activity.
• What do Event Related Potentials (ERPs) measure?

  The brain's electrophysiological response to specific events and stimuli through EEG data analysis.

  
• How do ERPs differ from standard EEGs?

  ERPs present a stimulus and look for activity related to that stimulus.
• What are the strengths and weaknesses of ERPs?

  Strengths:

  • More specificity than EEGs.
  • Excellent temporal resolution.
  • Non-invasive technique.

  
  

  Weaknesses:

  • Background noise must be eliminated, which is challenging.
  • Requires many repetitions of stimulus for results.
• What does an fMRI scanner measure?

  Blood oxygenation level (BOLD response) during a task.
• How does fMRI detect brain activity?

  By looking at oxygenated and deoxygenated hemoglobin in the blood flow.
• What are the strengths and weaknesses of fMRI scans?

  Strengths:

  • Non-invasive with no radiation.
  • High spatial resolution.

  
  

  Weaknesses:

  • Expensive and sensitive to head movement.
  • Poor temporal resolution; BOLD signal lags behind brain activity.
• What is the premise of fMRI regarding brain activity?

  More energy is required for active areas of the brain during a task.
• What is an example of a strength and weakness of fMRI?

  Strength: Non-invasive and risk-free.

  Weakness: Poor temporal resolution affecting data accuracy.
• How does the temporal resolution of fMRI compare to EEG/ERP?

  fMRI has a temporal resolution of 1-4 seconds, worse than EEG/ERP's 1 millisecond.
• What is the significance of temporal resolution in brain imaging?

  • It affects how quickly changes in brain activity can be detected.
  • Higher temporal resolution allows for more accurate predictions of brain activity onset.