Neurons Red in Tooth and Claw

There's an article summarizing recent brain development research at Johns Hopkins. We've known that neurons exposed to Nerve Growth Factor survive while their neighbors who might not be sucking up enough NGF die off. This article introduces another element: strong neurons actually harming weaker neighbors.

To test this idea they plugged these three additional genes into their computer model, assuming that the stronger connected nerve cell punishes its neighbors by releasing the two proteins capable of killing. The computer model showed again, that half the nerve cells die over time, but this time the death occurred over two to three days rather than 100 days, just as in living animals.