Figure 8. RAC* binding on levodopa vs. placebo, by diagnosis.

Differences in the RAC* binding response to levodopa between TS and control subjects, thresholded at uncorrected p = 0.001, in color, laid over the MRI template image in grayscale. a, b: Significant clusters, with blue lines crossing at the peak t value in midbrain ( a, three views) and in parahippocampal gyrus ( b). A third statistically significant cluster was centered at the posterior edge of the occipital lobe, but both the location and the observation that in this cluster the BP _ND on placebo was negative in half the subjects suggests that this cluster likely does not reflect specific binding. c: Levodopa-induced change in BP _ND, TS vs. control, in the clusters shown in A and B. R., Right; PHG, parahippocampal gyrus. Asterisks indicate that mean BP _ND differs significantly from zero. d: The blue lines cross at the voxel with the highest t value in the whole-brain SPM analysis of levodopa effect ΔDVR images ( t=11.62, 8 df).