Temporal Derivative in fMRI Data Analysis

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Temporal Derivative in fMRI Data Analysis

• Matthew Brown
• December 18, 2006

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Two Extremes

• Averaging
• no shape assumption
• vs.
• GLM with model haemodynamic curve
• assume shape
• potentially resistant against noise

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Middle Way

• GLM with modeled haemodynamic curve
• and related curves
• - eg temporal derivative of HRF
• Including more curves in GLM lets is fit data
  (and noise) better.

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Model HRF
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Model HRF Derivative
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Shifted HRF
Blue line is sum of HRF and its derivative.
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Shifted HRFs
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Shifting Forward
White line is HRF minus its its derivative.
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Temporal Derivative Map