From the "paper" itself :
we investigated a methodological issue: can valid, high resolution maps of science be derived from clickstream data and can clickstream data be leveraged to yield meaningful insights in the structure and dynamics of scholarly behavior? To do this we first aggregated log datasets from a variety of scholarly web portals, created and analyzed a clickstream model of journal relationships from the aggregate log dataset, and finally visualized these journal relationships in a first-ever map of science derived from scholarly log data.
What I learned quickly, though I knew it before is a startling disconnection between what we call "brain research" and "brain studies"
Though you might think that we should be discussing one freaking entity, obviously there is Cartesian dichotomy, even if it is not named as was originally stated "Mind-Body Dualism".
Another curious fact - one of the first sciences - Geography is almost non existent, represented just by one dot :)