Scientists partially restored the vision in blinded hamsters by plugging gaps in their injured brains with a synthetic substance that allowed brain cells to reconnect with one another, a new study reports.
If it can be applied to humans, the microscopic material could one day help restore sensory and motor function to patients suffering from strokes and injuries of the brain or spinal cord. It could also help mend cuts made in the brain during surgery.
In principle, it seems like reconnecting severed nerves ought to be easy -- all you have to do is splice a long wire.
In practice, it's been nearly impossible. The nerve bundles are mostly composed of axons, the long branches of individual nerve cells that conduct impulses. So to fix a severed nerve, you can't just connect the opposite sides of the break, you have to coax new axons to grow across it.
So these folks have found a matrix that allows the neurons to grow through it, much as they do in the developing brain.
Within 24 hours, all of the animals treated with SAPNS showed signs of healing; with time, the gaps in their brain tissues closed up completely.
In the adult group, vision was functionally restored within six weeks. In one animal, the severed nerve tract was restored to more than 80 percent that of a normal animal. In other studies, the researchers found that nerves needed to be only about 40 percent healed for animals to have functional vision.
This is the simplest task of neural repair, fixing a wire. Fixing brains -- or building them -- will take a bit more, since we don't understand the complex connections that allow things to happen. But this is good, very good.