Effect of injury to the dorsal funiculus of the thoracic spinal cord on micturition in decerebrate and freely-moving cats

Bladder sensation is transmitted both via the spinothalamic tract in the la teral funiculus and the dorsal system in the dorsal funiculus, We transecte d the dorsal funiculus in 10 female cats to clarify the functional roles of these two ascending pathways. The dorsal funiculus was transected at T10 i n 5 decerebrate and 5 freely-moving cats, and micturition parameters were c ompared before and after transection. Transection of the dorsal funiculus d id not affect any of the parameters of reflex micturition in the 5 decerebr ate cats. Within 1 week after transection, 4 of the 5 freely-moving cats us ed the normal micturition posture, but the remaining one performed micturit ion in a prone position as if she had lost micturition sensation. All 5 cat s urinated with a normal micturition posture by 2 weeks after transection. The mean single voided volume was decreased transiently up to 1 week, but r eturned to normal by 2 weeks after transection. None of the 5 cats had any residual urine before and after transection. Both the ascending and descend ing limbs of the micturition reflex pass through the lateral funiculus. Bla dder sensation is transmitted both via the spinothalamic tract coursing in the lateral funiculus and the dorsal system in the dorsal funiculus. The do rsal system may play a major role in the transmission of bladder sensation to the cerebral cortex, but may not be essential. Copyright (C) 2000 S. Kar ger AG, Basel.