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.