Fig. 2.

Differences in local gray matter volume estimates between chimpanzees and bonobos based on analysis of T1-weighted images. The t-statistic image is thresholded at t > 4.0 and overlaid on the common species gray matter template. The figure shows three coronal sections through the gray matter template at different anterior–posterior levels. Regions in blue have higher local gray matter volume estimates in bonobos; regions in yellow have higher local gray matter volume estimates in chimpanzees. The Y-coordinate is relative to Y = 0 at the anterior commissure.