Comparison of DOMS-related activation by contraction and physical stimulation in the insular cortex and ventral posteromedial thalamic nucleus (VPM).

<p>Multi studies of activation following both means of stimulation in a standardized Talairach brain. Clusters were calculated by GLM contrasts between painful and non-painful stimulation conditions (t≥5). Dark green: activation by painful contraction; light green: activation by painful physical stimulation; orange: intersection. <b>a, b.</b> coronal and sagittal section illustrating orientation of transversal sections in c and d. <b>a, b, c, d.</b> Physical stimulation resulted in much larger areas of activation bilaterally in the AIC (a, c) and the left VPM (d), while activation in the MIC and PIC largely overlapped with areas activated during the contraction-related task (b, c). <b>e, f.</b> timeline of the BOLD-signal (average over 5 stimulus periods) for painful contraction (red) versus physical stimulation (f) in the same area of the left MIC (circled cluster in c). Painless contraction, but not painless physical stimulation) leads to coactivation during painless contraction (blue) as seen in <b>Fig. 3</b>; <b>g, h.</b> timeline of the BOLD-signal (average over 5 stimulus periods) for painful contraction versus painful physical stimulation (red timelines) (f) in the same area of the left VPM (circled cluster in d). Again, painless contraction, but not physical stimulation leads to coactivation (blue timelines).