Acupuncture-Evoked Response in Somatosensory and Prefrontal Cortices Predicts Immediate Pain Reduction in Carpal Tunnel Syndrome

Figure 4

Group and difference maps of brain response during acupuncture. Local EA produced activation in contralateral primary somatosensory cortex (S1) and bilateral insulae and secondary somatosensory cortex (S2) and deactivation in ipsilateral S1. Distal EA produced activation in bilateral insula and S2. Verum EA (combined local and distal) produced activation in left S1 and bilateral insulae and secondary somatosensory cortex (S2) and deactivation in the medial prefrontal cortex (PFC) and right S1. Compared to sham EA, local EA produced greater activation in right insula and bilateral S2 and while greater deactivation in ipsilateral S1 and inferior temporal gyrus (ITG). Distal EA produced greater activation in bilateral S2 and greater deactivation in PCC. Verum EA produced greater activation in right insula and bilateral S2 and greater deactivation in right S1. Note: S1 was analyzed using a midsagittal plane flipped analysis (as S1 is known to be lateralized in activity relative to the stimulated side), while other regions were analyzed using a more conventional nonflipped analysis. All coordinates are in MNI space.