Figure 3. Results of the fMRS experiment. a, Group analysis of fMRI activation during CVS. Shown are significantly stronger activations during CVS than baseline (p < 0.05 FDR corrected, color coded in red to yellow) in a weighted random-effects group analysis for a total of 20 subjects overlaid on a template brain (right hemisphere). Activation at the junction of the parietal operculum and the posterior insula during CVS corresponds to PIVC. The white cross symbol shows the location of PIVC from a previous study (Frank et al., 2016b). b, Individual center of location of PIVC in the right hemisphere as defined by means of CVS for each subject in the fMRS experiment. Each dot shows the center of PIVC in a different subject. The results are overlaid on an inflated template brain with the recent cortical segmentation proposed by Glasser et al. (2016). The location of the enlarged section in the inflated brain is shown on the right. Across subjects, PIVC was centered at the junction of the parietal operculum and the posterior insula. 43, Area 43; FOP2, frontal opercular area 2; IG, insular granular complex; OP2-3, area OP2–3; OP4, area OP4; POL1, posterior insular area 1; POL2, posterior insular area 2. c, Location of the fMRS voxel (corresponding to the black square frame in the panel) centered on right PIVC as defined by significantly stronger BOLD activation during CVS than baseline (shown by red-yellow colors similar to those in a) in a sample subject. d, Mean concentrations (±SE) of Glx in right PIVC during low and high loads of visual attentional tracking (corresponding to tracking two and four disks, respectively) for 20 subjects. The concentrations of Glx were measured by a PRESS scan and are relative to tCr, a control metabolite taken from the same scan. e, Same as d but for GABA. The concentrations of GABA were measured by a MEGA-PRESS scan and are relative to NAA, a control metabolite taken from the same scan. **p < 0.01.