Eugene P. Duff1, Stephen M. Smith1, Mark W. Woolrich1, Bill Vennart2, Matthew A. Howard3, Steven C.R. Williams3, Steven J. Coen3
1FMRIB, University of Oxford, Oxford, UK; 2PGRD, Pfizer, Sandwich, UK; 3Institute of Psychiatry, Kings College, London, UK
fMRI pain studies sometimes record trial-by-trial ratings of pain intensity. However, the extent to which these ratings can benefit signal modelling has not been studied in detail. This study provides such an analysis. We find that modelling trial-to-trial variations in pain provided substantial improvement in the localisation of stimulus-related effects of interest. Improvements were greatest in regions of the pain matrix known to be involved with the processing of pain. We recommend that pain ratings be recorded and modelled whenever possible.
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