Conduction block due to demyelination at the ventral root exit zone in experimental allergic encephalomyelitis.

Histological and electrophysiological studies were performed in Lewis rats with experimental allergic encephalomyelitis (EAE) to determine the cause of the neurological signs. The ventral root exit zone of the spinal cord was shown to be a major site of demyelination and conduction block. It is concluded that demyelination-induced conduction block in this region is an important cause of hindlimb weakness and paralysis in Lewis rats with EAE.