Mammalian brains are incredibly dense with connections: with present technology, just building a computer that can replicate one per cent of a human’s brain technology requires the power of 250,000 desktop PCs. But, thanks to one new scientific paper, we now at least know how the synapses are organised.
To gain a deeper understanding of what’s going on inside a rat’s head — and, hopefully, one day our own — a team of scientists from USC constructed a database from 40 years of study of the rat brain, resulting in this database, a virtual ‘wiring diagram’ for the rat’s brain.
Then, the team conducted a network analysis on the connections, to try and understand the underlying structure. The result: neurons are built in a series of local networks, “layered like the shells in a Russian nesting doll”. Two local networks — vision and learning, and organ function — make up the inner shell, with another two making up the outer shell.
That gives the cerebral cortex the structure of a “mini-internet” — or any complex computer network, really. A series of increasingly larger local networks all connect together, working upwards until you end with the fibre-optic cables and data centres that make up the backbone of our internet.
Although discovering that rats are running their own little Facebooks in their heads doesn’t seem like much of a scientific breakthrough, understanding the structure moves us a step closer to creating a complete wiring diagram of the global central nervous system, which in turn moves us towards understanding cognition itself. Can’t keep Skynet waiting, after all. [Proceedings of the National Academy of Sciences]