LEVELS OF BRAIN STEM AND DIENCEPHALON CONTROLLING MICTURITION REFLEX

Abstract

The diencephalic and brain stem areas controlling the micturition reflex were localized by combining cystometry with transections of the neural axis at different levels. The minimal volume of fluid necessary to initiate micturition contraction (the micturition threshold) was used as the criterion for the relative activity of the micturition reflex. Female cats (35) were studied. The micturition threshold decreased sharply following intercollicular decerebration and moderately following supracollicular decerebration indicating that the cerebrum has some inhibitory effect on the micturition reflex and that the rostral midbrain has an additional inhibitory influence. Secondary supracollicular transections in trans-hypothalamic decerebrate animals greatly elevated the micturition threshold, indicating that an area exists between these 2 levels of transection which has a facilitatory effect on the micturition reflex. Conversion of supracollicular decerebrate to intercollicular decerebrate preparations greatly decreased the micturition threshold, further indicating that an area exists between these 2 levels of transection which has an inhibitory effect on the micturition reflex. Secondary subcollicular transections in intercollicular decerebrate animals completely abolished the micturition reflex indicating, in agreement with Barrington, that an area exists between these 2 levels of transection which has a facilitatory effect on the micturition reflex.