Spontaneous Activity: Signal or Noise?

It is thought that spontaneous electrical activity in the brain may contribute to the specifity of the neuronal connections laid down during development of the nervous system. David McCormick considers the evidence for this in a Perspective. A study of the visual system in awake baby ferrets that have not yet opened their eyes suggests that spontaneous activity could play a part in guiding and refining the formation of neuronal connections during development (Weliky and Katz).