Functional brain connectivity from fMRI studies has become an
important tool in studying functional interactions in the human brain
as a complex network. Most recently, research has started focusing on
whole brain functional networks at the voxel-level, where fMRI
time-signals at each voxel are correlated with every other voxel in
the brain to determine their functional connectivity. For a typical
4mm isotropic voxel resolution, this results in connectivity networks
with more than twenty thousand nodes and over 400 million links. These
cannot be effectively visualized or interactively explored using
node-link representations, and due to their size are challenging to
show as correlation matrix bitmaps.

In this talk, I present recent work from my group on a number of
methods for the visualization and interactive visual analysis of this
new high resolution brain network data, both in its matrix
representation as well as in its anatomical context. We have
implemented these methods in a GPU raycasting framework that enables
real-time interaction, such as network probing and volume
deformation, as well as real-time filtering. The techniques are
integrated in a visual analysis application in which the different
views are coupled, supporting linked interaction. Furthermore, we
allow visual comparison of different brain networks with side-by-side
and difference visualization. We have evaluated our approach via case
studies with domain scientists at two different university medical
centers.