Daron Gordon Owen1,2, Collin Franklin Clarke3, Sugantha Ganapathy3, Frank S. Prato1,4, Keith S. St. Lawrence1,2
1Imaging Program, Lawson Health Research Institute, London, Ontario, Canada; 2Medical Biophysics, The University of Western Ontario, London, Ontario, Canada; 3Anesthesia and Perioperative Medicine, The University of Western Ontario, London, Ontario, Canada; 4Imaging, St. Joseph's Hospital, London, Ontario, Canada
The cerebral representation of acute pain is well established, whereas that of tonic pain is not due to difficulties in applying functional imaging to prolonged stimuli. We used arterial spin labeling (ASL) to investigate the neural activation associated with tonic muscular pain. The use of ASL allows direct comparison between studies. Compared to our previous study incorporating both acute and tonic phases, we observed smaller CBF changes, and only in bilateral insula and frontal gyrus, despite similar pain levels. A likely explanation is that the acute phase of the previous study induced anxiety and distress, whereas our tonic pain stimulus did not.