Somewhere in the 200 million bases of the human genome is the information necessary to establish the basic wiring pattern of the nervous system. But just how that genetic information gets translated into specialized neurons, properly connected circuits, and the brain's vast information-processing capacity remains largely a black box. Scientists have been whittling away at the problem for decades, and some mechanisms that control neural specification are becoming clear.
One reason: Scientists are studying the brain through the spinal cord. "We are all studying the spinal cord and the sensory ganglia .... [because] it is simpler," says Eric Turner, assistant professor at University of California, San Diego. "We can define the system and know what its normal connections look like at a much more complete level than we can know what the forebrain and its connections look like."
While he ultimately wants to understand how brain wiring works, Turner says ...
