Spinal cord function

The spinal cord is a two-way channel for messages. Its role is to carry information from the brain out to the periphery, which is everything outside the brain and the spinal cord, and to bring it back in the opposite direction.

Those messages do not travel jumbled together; they travel in lanes. The white matter of the spinal cord, which is the part made of nerve fibers, is organized into tracts, each one with its own cargo. Ascending tracts carry information up from the sensory receptors, the sensors spread throughout the body, to the higher levels of the central nervous system. Descending tracts make the opposite trip: they carry information down from the central nervous system to the periphery.

And there is a division of labor that generally holds: the regions at the back handle sensory functions and the ones at the front are associated with motor functions. That shows up in the horns, which is what those front and back zones are called: the anterior horn contains motor nerves, the ones that send the command to the muscle, and the posterior horn contains the sensory ones, especially those that carry pain and temperature.