More than any other part of the brain, the cerebral cortex makes us human. Through the electrical activity of the neuronal networks packed into the brain’s undulating outer surface we sense our environment, use and understand language, and separate good and evil. So, then, the biologist’s mantra, “form follows function,” means that when we learn about brain structure, we learn about our very nature.
Last March a team of scientists used a new and powerful scanner to peer into the cerebral cortex and other underlying structures with an unprecedented level of resolution. What they found surprised them: rather than an incomprehensible bundle of twists and turns, the basic structure of the brain is a simple, three-dimensional grid. The new discovery could guide neuroscientists as they study the brain’s form and function, and lead to new insights into the organizing principles of the brain.
The grid structure was seen in our brains and those of our primate cousins as well. Scans were performed on the postmortem brain of four different monkey species – rhesus, marmoset, owl, and galago – as well as on the brains of living humans. Zooming in on major brain pathways they continually observed other pathways that crossed perpendicularly to form checkerboard-like, two-dimensional sheets. These 2D sheets stacked up alongside adjacent 2D sheets to form a 3D grid. And, it turns out, that the grid pattern is not only found in the cortex but is continuous with lower brain structures including centers for memory and emotion.