Figure 2.
A, Bar graph illustrating mean treatment-mediated changes in the expression of the PDRP measured in scans of CMR (filled bars) and CBF (open bars). At the network level, a significant dissociation between the CMR and CBF treatment responses (p < 0.001) is present with LD (left), but not with STN DBS (middle) or in PD controls (PD CTRL) (right) undergoing repeat imaging on stable doses of dopaminergic medication. ***p < 0.005; **p < 0.01; *p < 0.05, post hoc Bonferonni comparisons of ON versus OFF values for each treatment group. B, Correlation between disease duration and PDRP-related CBF increases during levodopa (LD) infusion (ΔCBF; see text). A significant correlation (r = 0.75, p = 0.01) was found between these variables. PD patients undergoing LD infusion with or without dyskinesia are represented by open and filled symbols, respectively. C, Bar graph illustrating measures of flow–metabolism dissociation during treatment for the motor-related PDRP network (see Materials and Methods). The dissociation index was significantly different for the three groups (p < 0.004), with greater dissociation in the LD group (filled bar) relative to both STN stimulation (gray bar) (p < 0.04) and PD controls (open bar) (p < 0.005). D, None of the three groups exhibited significant flow–metabolism dissociation in the response of the PDCP. Error bars indicate SEM.