The human brain is a crowded place. It contains an estimated 100 billion neurons, connected to one another by a million billion synapses. Neuroscientist Olaf Sporns of Indiana University, cellular biologist Jeff Lichtman of Harvard, and computational neuroscientist Sebastian Seung of MIT are mapping these connections, aiming to eventually create a “connectome” of an entire brain.
Each neuron can be thought of as a cellular decision maker: It receives a multitude of signals and decides which ones to pass on and which to shrug off. Figuring out the interactions of all these decision makers would move researchers closer to creating models of how we perceive our surroundings and store memories. “One of the biggest hypotheses in neuroscience is the idea that memories are stored in the connections between neurons,” Seung says. With a connectome, individual memories might be read from neural connections.