The Brain: The Connections May Be the Key

Once we model the connectome—the million
billion points of contact between neurons in the brain—we’ll glimpse the anatomy of the mind.

Carl Zimmer in Discover:

Neuroscientists know that the brain contains some 100 billion neurons and that the neurons are joined together via an estimated quadrillion connections. It’s through those links that the brain does the remarkable work of learning and storing memory. Yet scientists have never mapped that whole web of neural contact, known as the connectome. It would be as if doctors knew about each of our bones in isolation but had never seen an entire skeleton. The sheer complexity of the connectome has put such a map out of reach until now.

The strange forest on Berger’s desktop is one small but crucial piece of the picture. It is just three neurons large—“a thousandth the width of a human hair,” Seung says—but it shows every detail of their connections down to the smallest bumps and spikes. Taking advantage of the latest advances in electron microscopy and computer-controlled imaging, Seung and his team are creating some of the most detailed three-dimensional reconstructions of cortical gray matter ever made.

Seung believes that by the end of this century, his successors will have mapped the connectome of an entire human brain. “Our descendants will look back on these achievements as nothing less than a scientific revolution,” he writes in his new book, Connectome: How the Brain’s Wiring Makes Us Who We Are. As scientists gain the power to see the brain in its full complexity, he argues, they will finally be able to answer some of the most fundamental questions about the mind.

More here.