In tabes dorsalis demyelination occurs in all areas, EXCEPT:

Tabes dorsalis Late manifestation of syphilis Symptoms and signs of demyelination of the posterior columns, dorsal roots, and dorsal root ganglia. Symptoms are Ataxic wide-based gait Foot drop Paresthesia; Bladder disturbances; Impotence; Areflexia; and Loss of positional, Deep-pain, and Temperature sensations. Trophic joint degeneration (Charcot's joints) can result from loss of pain sensation. Optic atrophy occurs in tabes. Ref: Harrison, E-18, P-1383