THE CONTRIBUTION OF CRANIAL-NERVE NUCLEI TO THE SHORT-LATENCY VESTIBULAR EVOKED-POTENTIALS IN CAT

The object of this study was to assess the contributions of various cr anial nerve nuclei to the short latency vestibular evoked potentials ( VsEPs) in cat. The following nuclei were investigated: vestibular nucl ei, and 3rd, 6th and 10th cranial nerve nuclei. In unilateral labyrint hectomized cats, suboccipital craniectomy and partial cerebellectomy w ere carried out in order to place bipolar electrodes into the neural s tructures under investigation. The surface recorded VsEPs (far-field) were compared with the potentials recorded intracranially in response to the same acceleration impulses. The exact locations were later conf irmed histologically. Reversible lesions also were induced by injectin g of lignocaine 2%. The results indicate that the 2nd wave (P-2) is ma inly generated in the superior and medial vestibular nuclei. The 3rd, 6th and 10th cranial nerve nuclei apparently contribute to the later w aves of the VsEPs, particularly P-3 and P-4.