Figure 2.

Group differences in relative regional cerebral metabolic rate for glucose, independent of sleep-wake state. We assessed relative regional cerebral metabolic rate for glucose (rCMR_glc) in a sample of 44 patients with primary insomnia (PI) and 40 good sleeper controls (GS) during wake and nonrapid eye movement (NREM) sleep. To assess group (PI-GS) differences independent of sleep-wake state, we averaged relative rCMR_glc values across wake and NREM sleep for each voxel in each participant. The color bar represents t values; blue indicates regions where PI had lower relative rCMR_glc than GS across wake and NREM sleep, including the (a) bilateral precuneus/posterior cingulate cortex (b) bilateral anterior cingulate/medial frontal cortex, and (c) right hippocampus/amygdala, and (d) right fusiform gyrus, P_{3DC_corrected} < 0.05 for all. A full list of brain regions involving these clusters is presented in Table 4. We extracted the voxelwise data from anatomically distinct regions of the circled clusters, (a) the left precuneus/posterior cingulate and (b) the right anterior cingulate cortex and plotted these data to the right. In these line graphs, the closed circles connected with a solid line represent extracted average rCMR_glc from the respective regions for PI, and the open circles connected by a dotted line represent GS. Error bars represent the 95% confidence interval computed voxelwise within each cluster. L = left; R = right.