Kate WilletteOne of SCI research’s biggest and most heated disagreements may be nearing a resolution. At issue is: After a spinal cord injury, what exactly prevents a surviving axon from making its way through the injury site to reconnect with surviving axons on the other side?

Over years of heated debate, two camps have emerged. We’ll call them Team Scar and Team Poison. Team Scar is positive the problem is molecules produced by astrocytes, which are one of the three main kinds of spinal cord cells. Team Scar asserts these molecules form a barrier that is both physical and chemical — a scar.

Team Poison is just as certain that the culprits are different molecules found in myelin, the white coating that serves as a wrapper around healthy axons. Team Poison’s proposition is that these myelin-made molecules are toxic to growing a