3D rendering of DEC map

Hi all,

Is there a way to only show the major white matter tracts in a 3D rendering of a DEC map?
I played with view option parameters but couldn’t get something better than this:

While the lower threshold may help to crop some of the grey matter, I doubt it is going to provide you with the kind of result you’re looking for. For DEC images, the threshold is applied to the norm of the vector; so the question becomes: is the norm of the vector smaller in the superficial white matter than it is in the major white matter bundles? The answer to that question will depend on what is encoded in the norm of the DEC image:

  1. If it’s DEC FA, then essentially increasing the lower threshold will show you only voxels with a high FA, which might give you some of the major white matter bundles.

  2. For e.g. DEC FOD, the norm in the superficial white matter is actually not all that different to the major white matter bundles; there may be multiple fibre bundles rather than one, but the total density of fibres tends to not actually vary that much (at least using our diffusion model estimates).

  3. For DEC TDI, it will depend on the tracking; with whole-brain tracking, especially with WM seeding, the major bundles tend to be over-represented, and so exploiting the lower threshold may isolate some of the major white matter bundles; but SIFT / SIFT2 will converge the behaviour toward that of point 2, since the streamlines densities are converged toward the underlying AFD.

I suspect that if you want to visualise only the major white matter bundles, you will have more success actually isolating the white matter bundles :man_shrugging: