"It turns out that the pathways in your brain — the connections between neurons — are almost perfectly grid-like. It’s rather weird: If you’ve ever seen a computer ribbon cable — a flat, 2D ribbon of wires stuck together, such as an IDE hard drive cable — the brain is basically just a huge collection of these ribbons, traveling parallel or perpendicular to each other. There are almost zero diagonals, nor single neurons that stray from the neuronal highways. The human brain is just one big grid of neurons — a lot like the streets of Manhattan, minus Broadway, and then projected into three dimensions. (...) “Before, we had just driving directions. Now, we have a map showing how all the highways and byways are interconnected,” says Van Wedeen, a member of the Human Connectome Project." - Amira

“Brain wiring is not like the wiring in your basement, where it just needs to connect the right endpoints. Rather, the grid is the language of the brain and wiring and re-wiring work by modifying it.” Curiously, it seems like this network of highways and byways is laid out when we’re still an early fetus. At a very early stage, our brains form three “primal pathways” that traverse our brains horizontally, vertically, and transversely. The NIH scientists now think that those early connections act as markers, forcing the continued growth of an orderly, grid-like structure. Apparently such a setup is more amenable to evolutionary adaptation, too." - Amira