"The brain appears to be wired in a rectangular 3D grid structure, suggests a new brain imaging study. (...) “Far from being just a tangle of wires, the brain’s connections turn out to be more like ribbon cables — folding 2D sheets of parallel neuronal fibers that cross paths at right angles, like the warp and weft of a fabric,” (...)
“The wiring of the mature brain appears to mirror three primal pathways established in embryonic development.” (...) “Before, we had just driving directions. Now, we have a map showing how all the highways and byways are interconnected,” said Wedeen. “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.”
"By looking at how the pathways fit in the brain, we anticipated the connectivity to resemble that of a bowl of spaghetti, a very narrow and discreet object," (...) "We discovered that the pathways in the top of the brain are all organized like woven sheets with the fibers running in two directions in the sheets and in a third direction perpendicular to the sheets. These sheets all stack together so that the entire connectivity of the brain follows three precisely defined directions." (...)
"This is the first time it has ever been determined that the geometry of the brain is described by a three-dimensional grid," (...)
"The research took MRI scanners and new mathematical algorithms to determine a geometry to the relationship of nearby pathways in the brain so that each pathway was part of a two-dimensional sheet of pathways that together looked exactly like a woven sheet of fabric," Each pathway was part of a parallel series next to it crossed by a perpendicular series at a right angle, together which formed a woven grid.
The structure was part of a three-dimensional scaffold connections of the brain conformed to the extremely simple three-dimensional structure, a single woven grid with fibers in only three axes. By using diffusion MRI and mapping the three-dimension motion of the water molecules in the brain, the scientists ran the maps through mathematical algorithms that inferred from the water motion pattern the fiber architecture of the tissue of the brain." -- http://www.nsf.gov/news/news_summ.jsp?cntn_id=123711&org=NSF&from=news