Spinal and spino-bulbo-spinal reflexes in rats with experimental allergic encephalomyelitis

Experimental allergic encephalomyelitis (EAE) often produces complete hindlimb paralysis in rats. Stimulating the dorsal root at L5 was found to produce hindleg twitches in EAE rats with complete hindlimb paralysis. In addition, it was possible to record a monosynaptic response from the ventral root at L5 after stimulating the ipsilateral dorsal root (L5) in these rats. It was also possible to elicit a reflex at L5 which was shown to involve the central nervous system above the spinal cord level. These experiments demonstrated that the motoneurons and the muscles of the hindlimbs and the spinal cord segment innervating the hindlimbs remain functional in EAE paralyzed rats. This suggests that the paralysis may be caused by dysfunction of descending pathways of supraspinal origin.