( -tuning before establishing their final...)First real-time view of developing neurons reveals surprises, say Stanford researchers

Still, the experiments mark the first time researchers have been able to watch neurons in an entire region of the brain as they fire one by one in real time. The technical savvy involved in monitoring neurons will allow researchers to conduct experiments that were previously not possible.

While the research showed neurons firing in a more mature way than expected, it also revealed that neurons take their time establishing the final wiring of the brain. Young neurons send out branches in all directions in the hopes that some branches will connect to other neurons and form synapses that transfer information. As the neuron matures, some of these branches form stable synapses while others recede. This trial-and-error process is what establishes the final interconnected mesh of the brain.

Because the group could see the full branching structure of a neuron each time it fired, they could watch the branches grow and recede like a tree waving in the wind, losing the occasional twig. Over time, the network of branches stabilized into the mature form.

"We're looking at a dynamic process that nobody has ever seen before," Smith said.

Understanding how neurons mature into their adult role goes beyond zebra fish and their ability to see their eventual planktonic prey. "Probably these same processes are happening in our own brains all the time," Niell said. When people learn new skills or add memories to their overstuffed brains, new connections are required to retain that information.

Some diseases also seem to be caused by brain connections not forming normally. Dyslexia, for example, may be caused by connections failing to form between certain brain regions, whereas schizophrenia may result from too many connections forming.

What's more, any cure for spinal cord injuries will require new neurons to form the appropriate connections.