[Surgical repair of spinal cord injuries]

Spinal cord rupture is still incurable. Axons regenerating from the brain do not advance through the damaged cord towards peripheral motoneurons. The reasons for this "nonpermissiveness" are unclear. The author's research started in 1980 on rats and monkeys, with attempts to connect the lateral tract of the cord, upstream of the lesion, to the muscles, by means of autologous grafts. This operation was subsequently performed on fully informed volunteers with total cord rupture between T8 and T11. The first patient regained a rudimentary but effective gait. This connection of upper motoneurons with peripheral muscle nerves works even when the activating axons derive from cells dispersed among different regions of the brain cortex but that fire together, providing selective contraction of single muscles. Furthermore, this functioning occurs even though upper motor neurons use the neurotransmitter glutamate, whereas motor endplates normally have acetylcholine receptors. In fact, immunoblot analysis of ChAT VAChT, Vglu-1 GluR1 and GluR2 shows that motor endplate receptors switch from choline to glutamine.