Evoked responses in the anterior brain stem of cats during urinary bladder contractions

Abstract

Neural activity in various regions of the anterior brain stem were studied during spontaneous bladder contractions using evoked potential techniques in awake, immobilized cats. Potentials were evoked in diencephalic and mesencephalic regions by stimulation of the sciatic nerve. Each potential was classified into one of five categories depending on the bladder pressure. Compared to control, some potentials in other categories were either enhanced or suppressed during the contraction or, in some cases, a combination of both occurred. The latter triphasic responses consisted of either an increase or a decrease during the pre- and postcontraction periods with the opposite effect during the contraction. Responses were particularly evident in red nucleus, superior colliculus, substantia nigra, central gray, and mesencephalic reticular formation. These results were interpreted with respect to previous studies which associate these structures with bladder function and in terms of brain stem integration of multiple sensory inputs.