[elektropionir]

They did diffusion tensor imaging. What this does, using MRI, is determine the local anisotropy of water flow in each voxel. You assume that this anisotropy aligns with with the axis of axons, since they limit the diffusion of water across their axis (water diffuses along them). You can then use the principal directions of the diffusion tensor to estimate in what direction the water, i.e. the axons are "flowing" giving you an approximate picture of how axons connect different parts of the brain.

[caust1c]

Neat! So it's like an EM Flux measurement, but for the brain?! If so, that's fascinating :-)

[tbenst]

MRI is ~5 orders of magnitude less precise than EM. Not even close to cellular resolution, let along single axon resolution. You can only see axon tracts, where thousands of axons may make up one pixel.

[leemailll]

The problem is the voxels is not the same for each species considering brain size, and the limit of machine’s resolution.