John McGonigle1, Andrea L. Malizia2,
Robin Holmes3, Majid Mirmehdi1
1Computer Science, University of
Bristol, Bristol, United Kingdom; 2Psychopharmacology Unit,
University of Bristol, Bristol, United Kingdom; 3Medical Physics,
United Bristol Healthcare NHS Trust, Bristol, United Kingdom
Data-driven
analysis is useful in pharmacological MRI where there may be no model of
neural response available a priori. It is recognised that the signal
complexity of noise will usually be higher than any signal of interest. Renyi
entropy may be used to discover the complexity of a time frequency
representation of a voxel time course. Its application here at every voxel in
a region of interest across several subjects shows it is capable of
discovering drug effect which is not found when the same analysis is carried
out on placebo data.