I came across this page from an Emeritus Professor at California State University, Chico.
I found it interesting, and easy to understand. The Parietal Lobe seems to be most applicable for explaining how and why Italic Bookmarks work the way they do. It is part of a more extensive view of the brain and central nervous system, but this particular page gives some basic anatomy of the brain as well as a description of the general function of each region.
Source: Patrick McCaffrey, Ph.D. Emeritus Professor