Ways of scanning the brain: scanning techniques, including functional Magnet Resonance Imaging (fMRI); electroencephalogram (EEG) and event-related potentials (ERPs); post-motem examinations

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  • scanning began in the 1970s with x-rays
  • scans are used to: unstand relationship betweeen brain structure and brain function (speech/memory); identify what goes wrong in brain disorders such as schizophrenia; locate and treat brain tumours, epilepsy, and other disorders with precision. they can also be used in brain surgery to treat OCD, depression and other psychological disorders

fMRIs were developped in the 1990s. They are MRIs that have been adapted to measure functional changes in brain activity. They detect regions in the brain where there are activity-related changes in levels of blood flow, which helps to accurately determine which brain regions are active in each task. They:

  • measure change in brain activity in real time
  • rely on different properties of oxygenated and de-oxygenated blood
  • provide the clearest image - good for determining localisation of function
  • only show blood flow, meaning they need to be combined with other methods
  • are being developped to potentially identify whether a person is innocent or guilty in court
  • are non-invasive
  • have been used to try and find the causes and differences of people with OCD`s differences in brain function
  • use a magnetic field on the haemoglobin
  • show activity 1 second after it occurs and is accurate to 1-2mm

fMRI superseded PET scans.

Menzies et al (2008) conducted a meta-analysisof numerous fMRI scans / studies. In many of these they tried to provoke symptoms of OCD and discovered that there was generally greater activity in excitatory than inhibitionary receptors. this indicates that fMRIs are more detailed than PET scans.

  • hippocampus is more active in episodic memory
  • anterior temporal lobe is more active in semantic memory
  • basal ganglia is most active in procedural memory

fMRI evaluation:

  • temporal resolution is not as good as it could be…

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