fMRI: Biological Basis and Experiment Design Lecture 4

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fMRI Biological Basis and Experiment
DesignLecture 4

• History
• Basic mechanism
• Outstanding questions

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movie of steric conformations, from wikipedia.com
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(No Transcript)
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Basic BOLD
... blood oxygenation level-dependent (BOLD)
contrast a change in the signal strength of
brain water protons produced by the paramagnetic
effects of venous blood deoxyhemoglobin. Ogawa
et al. 1993

• Signal inversely proportional to deoxyhemoglobin
  concentration
• CBF cerebral blood flow
• increased CBF increases signal strength
• CBV cerebral blood volume
• increased venous blood volume decreases signal
  strength
• CMRO2 cerebral metabolic rate of oxygen
• increased CMRO2 decreases signal strength

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Harrison, Harel et al., Cerebral Cortex 12225
(2002)
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Discussion papers

• Spikes versus BOLD what does neuroimaging tell
  us about neuronal activity?
• David Heeger, Alex Huk, Wilson Beisler Duane
  Albrecht
• Nature Neuroscience 3(7)631.
• Neurophysiological investigation of the basis of
  the fMRI signal
• Nikos Logothetis, Jon Pauls, Mark Augath, Torsten
  Trinath Axel Oeltermann
• Nature 412150.
• Separate spatial scales determine neural
  activity-dependent changes in tissue oxygen
  within central visual pathways,
• Jeffrey Thompson, Matthew Peterson, Ralph Freeman
• Journal of Neuroscience 25(39)9046