This is what your brain looks like when you have all the neurons in the right places. Here, cells in different layers of the visual cortex show up as brilliant pink, yellow, and blue, depending on how deep they are in the brain (the colors are artificial).

But don't get too attached to this arrangement. In order to grow and learn, this brain is going to have to change. To be the marvelous organ of adaptability that it is, the brain must constantly remodel itself, storing new memories and mastering new lessons.

This image allows researchers at the Picower Institute for Learning and Memory at MIT to observe that fine-tuning process in action. Every few days they take another look at the same patch of visual cortex of a living mouse (0.5 millimeter square), observing which neurons remain in close contact and noticing where a cell has pulled back from its old neighbors to make new contacts.