Ed. note: Last week we wrote about Jurriaan Peters, MD’s brain network analysis in children with autism. In the second of our two part series on brain mapping, we talk about ways of mapping the brain’s physical wiring.

At the most basic level, the brain is a collection of wires, albeit a really complex one.

But how during development do nerve fibers thread their way through the growing brain and make the right connections?

The answer to that question could reveal more about the nature of conditions like autism spectrum disorders—which, as we reported about a year and a half ago, seem to have their roots in structurally altered brain pathways.

“We know very little about what’s happening in the developing brain in three dimensions,” says Emi Takahashi, PhD, a researcher in the Fetal-Neonatal Neuroimaging & Developmental Science Center (FNNDSC) at Boston Children’s Hospital. “With histology techniques, we can achieve a two-dimensional view over small areas, but it’s hard to know which fiber bundles are growing in which ways during different stages of development in the whole brain.”

But new MRI-based technologies are quickly closing that knowledge gap, giving us our first high-resolution peek into how the developing brain wires itself up.

Using something called high angular resolution diffusion imaging (HARDI) MRI, Takahashi and her colleagues (including neuroradiologist and FNNDSC director P. Ellen Grant, MD) can trace the three-dimensional pathways within the growing brain via stunning images like these:

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