FIG. 2.

Parietal–frontal circuits associated with the IPS. Parietal–frontal circuits identified using intrinsic functional connectivity analysis of the intraparietal sulcus (IPS), a “core” region involved in basic magnitude judgment and arithmetic. (A) IPS region of interests (ROIs) derived from cytoarchitectonic maps for the three subdivisions of the IPS: hIP2 is the lateral and anterior subdivision of the IPS (blue, dark gray in the print version); hIP1 is the subdivision located posterior to hIP2 (green, gray in the print version); and hIP3 is the posterior subdivision of the IPS (red, light gray in the print version). (B) Functional connectivity maps associated with hIP1, hIP2, and hIP3. The color (different gray shades in the print version) code represents voxels correlated with each source ROI. The IPS has significant connectivity with distributed frontal (MFG and PMC) and parietal (SMG and SPL) cortical regions in both hemispheres. Additional functional circuits associated with the ventral-occipital temporal cortex are not shown. hIP, human intraparietal; MFG, middle frontal gyrus; PMC, premotor cortex; SMG, supramarginal gyrus; SPL, superior parietal lobule.

Adapted from Uddin, L.Q., Supekar, K., Amin, H., Rykhlevskaia, E., Nguyen, D.A., Greicius, M.D., Menon, V., 2010a. Dissociable connectivity within human angular gyrus and intraparietal sulcus: evidence from functional and structural connectivity. Cereb. Cortex 20, 2636–2646.