studying the brain

• what is fMRI?


  Functional Magnetic Resonance Imaging
• how do fMRIs work?


  -> neurons in the brain that are the most active use the most energy

  -> energy requires glucose and oxygen

  -> oxygen is released for use for active neurons and so the haemoglobin becomes deoxygenated

  -> deoxygenated haemoglobin has a different magnetic quality from oxygenated haemoglobin. an fMRI can detect these different magnetic qualities and create a dynamic 3D map of the brain
• what is temporal resolution?


  the time interval it takes for activity to show after it has taken place
• what is the temporal resolution of fMRI?

  1-4 seconds
• what is spatial resolution?

  accuracy, i.e. how close two components can get to one another before they are not distinguishable as seperate
• what is the spatial resolution of fMRI?

  1-2mm
• what is EEG?


  Electroencephalogram
• how do EEGs work?

  electrodes measure brain activity by reading the action potential. small eletrical charges are detected by the elecrodes and are graphed. there are four types of EEG patters, alpha, beta, theta and delta
• what is amplitude in EEGs?

  the intensity or size of activity
• what is frequency in EEGs

  the speed of the activity
• what are synchronised patterns? (EEG)


  recognisable waveforms (alpha, beta, theta, delta)
• what are desynchronised patterns? (EEG)


  no pattern
• what waves are associated w light sleep?

  alpha
• what waves are associated w deeper sleep?

  delta and theta
• what is an ERP?


  event-related potentials
• how do ERPs work?

  use electrons

  a stimulus is presented to a participant, and a researcher looks for activity related to that stimulus

  the stimulus is usually presented 100s of times and an average response is graphed (averaging)
• what is latency? (ERPs)


  the time interval that occurs between the presentation of the stimulus and response
• what are sensory ERPs?

  ERPs with a latency of < 100 milliseconds
• what are cognitive ERPs?

  ERPs with a letency of > 100 milliseconds
• why is the temporal resolution of ERPs/EEGs a strength?


  they show activity every miilisecond, recording activity in nearly real time
• why is the spatial resolution of EEGs/ERPs a weakness?

  they only show superficial general areas of the brain
• what is a benefit of post-mortem studies?

  allow for a more detailed examination
• what scans are non invasive?

  fMRIs, EEGs and ERPs are all non invasive; benefit as does not harm the patient
• what scans are invasive?

  PET scans used radiation