Some questions for discussion:
- MRI: What are the capabilities of the current tractography methods, and what are the fundamental limitations?
- Postmortem tissue preparation: How can white matter structure be best preserved after death?
- Sectioning and collection: What is the state of the art in automated cutting and collection of brain sections?
- Light and electron microscopy: What are the capabilities of these methods, and can they be scaled up to the human
brain?
- Spatial resolution: What is the minimum sizeof axonal bundles in the white matter, and what spatial resolution is
necessary for a complete map of white matter connectivity?
- Validation: Can microscopy and MRI be combined to generate datasets for the testing and validation of tractography
algorithms based on MRI data?
- Sparse vs. dense reconstruction:In sparse reconstruction, only one or a few tracts are traced in each brain, and
many brains are analyzed to build up a map of white matter. In dense reconstruction, all tracts are traced in a single
brain. What are the relative merits of these approaches?
- Structural vs. "functional" connectivity: Many researchers refer to spatial correlations in fMRI activation
as "functional connectivity."
How are such activity correlations related to genuine structural measurements of connectivity?
- Cortical parcellation: The cerebral cortex is currently divided into areas based on multiple structural and functional
criteria. Could improved information about connectivity eventually make it the only criterion for parcellation?
- Connectopathies: How can we identify abnormal connectivity using both in vivo and postmortem studies, and relate
it to pathological genes and behavior?
- Beyond diagram making: White matter connectivity played a central role in the 19th century neurologists' approach to
brain function, but they were later derided as mere "diagram makers." How much impact will improved knowledge of
white matter connectivity have on our understanding of brain function?

 

In March 2010, we will gather leading researchers studying brain connectivity using the methods of MRI and microscopy. These methods are complementary because MRI can be applied in vivo but has low spatial resolution, whereas microscopy has high spatial resolution but is applied postmortem. We believe that it is time to bring together the MRI and microscopy communities to discuss the prospects for a complete map of the white matter connectivity of the human brain, as well as the implications of such a map for brain function.