The Brain Grid

Connections in the brain aren’t all tangled up – they’re organized into a grid of tightly-knit bundles, says a new study.

By applying mathematical analysis to the latest imaging technology, scientists have discovered that connective pathways are knit into a three-dimensional geometric pattern.

When scientists first set out to map the connections in a brain, they quickly found that the task was kinda like trying to organize all the cords tangled up behind your desk – except that the plugs number in the trillions, and many of the connections can inhibit others.

This complexity means we depend on super-fast computers to crunch vast amounts of data and render it into images and videos we can study (and appreciate as beautiful).

As researchers sent more and more powerful computers on quests for patterns in this data, they began to notice something extraordinary: the brain’s structural networks were just the hardware for an intricate array of interconnected functional networks – the brain’s software.

In the past few years, scientists have discovered that some of these functional networks lie at the roots of conscious awareness, while others shape the gradual mental changes we undergo as we age. In short, the more we study these networks, the closer we get to peering directly into our own consciousness through scientific instruments.

But the fun thing about science is, once in a while, someone comes along and digs up some totally unexpected treasure – which is exactly what a team led by Van Wedeen at the Martinos Center for Biomedical Imaging at Massachusetts General Hospital did this month.

A grid of fibers, bein' all interwoven and stuff. (Science Note: there aren't actually tiny arrows in the brain.)

As the journal Science reports, the team used diffusion spectrum MR imaging – a cutting-edge technology developed by Wedeen himself – to map the brains of human volunteers and other primates. By applying computerized mathematical analysis to the mountain of data they gathered, the researchers stumbled on something no one expected:

The cerebral fiber pathways formed a rectilinear three-dimensional grid continuous with the three principal axes of development.

And within that grid, individual nerve fibers are interwoven in consistent patterns:

Cortico-cortical pathways formed parallel sheets of interwoven paths in the longitudinal and medio-lateral axes, in which major pathways were local condensations.

What’s more, these patterns weren’t unique to humans:

Cross-species homology was strong and showed emergence of complex gyral connectivity by continuous elaboration of this grid structure.

In other words, monkey brains are organized along these same lines. This means we’ll be able to apply this kind of pattern analysis to other species’ brains, and begin to pinpoint where this organizational structure first emerged in our evolutionary history.

And now that we’re getting close to pinpointing the ancient origins of the basic vertebrate brain layout, we may soon be able to trace the evolution of our brain’s connective structure right back to its earliest ancestors.

The more neuroscience mysteries we solve, the more seem to appear on the horizon. And the more we investigate, the closer we get to some very slippery (and provocative) questions: What is human consciousness? When did it first emerge? What’s it evolving into now?

And most importantly, when do we get to see the animated version?

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