spinal cord is not severed, bruised and damaged, leading to bleeding from local blood vessels and swelling
Cells from the immune system infiltrate the area of primary injury, which expands for several days as local pathological processes continue in a cascade of secondary injury.
The primary and secondary injuries cause the death of neurons and oligodendrocytes, resulting in the disruption of synaptic connections and the demyelination of axons.
Demyelination of surviving intact axons greatly impairs action potential message conduction, and can render remaining connections useless.
By several weeks after the initial injury, the area of tissue damage has been cleared away by microglia from the CNS and macrophages from the immune system, and a fluid-filled cavity surrounded by a glial scar made up of astrocytes is left behind.
Molecules that inhibit regrowth of severed axons are expressed at this site. This fluid-filled cavity, called a syrinx, now forms a barrier to the reconnection of the two sides of the damaged spinal cord.
a surprising amount of the basic circuitry to control movement and process somatosensory information can remain intact.
because the spinal cord is arranged in layers of circuitry. Many of the connections and neuronal cell bodies forming this circuitry above and below the site of injury survive the trauma.
The goal of spinal cord injury research is to reconnect the wiring that controls muscle movement and provides sensory information to the brain.
can neurons in the spinal cord regenerate and make not only new connections, but the correct connections ?