Graded cutaneous electrical vs thermal stimulation in humans shows different insular and cingulate cortex activation.
Pain can result from various sensory input modalities. To elucidate the differences of cortical responses to graded electrical and thermal stimulation, functional magnetic resonance imaging (fMRI) results of two studies using the same stimulation paradigms but different modalities with 15 healthy subjects each are compared. During painful electrical stimulation contralateral dorsal posterior insula and ventral posterior anterior cingulate cortex (ACC) activated more. During thermal stimulation, there was more activation in ipsilateral primary motor area (MI)/primary sensory area (SI) complex and premotor areas as well as dorsal posterior ACC. Thus electrostimulation preferably activates structures of the lateral pain projection system resulting in contralateral dorsal posterior insula and ventral posterior ACC activation. During thermal stimulation, more dorsal areas of the posterior ACC activated. The activation of ipsilateral MI/SI complex and premotor areas may be attributed to the slower perception of thermal stimuli and resulting re-evaluation. This has to be taken into account in the interpretation of other cross-modality studies as well.
Department of Diagnostic and Interventional Radiology, University Hospital, Ulm, Germany. freund-ulm@t-online.de
Wolfgang
W
Freund
Arthur P
AP
Wunderlich
Gregor
G
Stuber
Bernhard
B
Landwehrmeyer
Roland
R
Klug
D000328:Adult; D000344:Afferent Pathways / Q000098:blood supply / Q000502:physiology; D001703:Biophysics; D002540:Cerebral Cortex / Q000098:blood supply / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D006179:Gyrus Cinguli / Q000098:blood supply / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D017288:Pain Threshold / Q000502:physiology; D011601:Psychophysics / Q000379:methods; D012867:Skin / Q000294:innervation*; D013696:Temperature
D010100:Oxygen