Vagal representation in the cerebellum of the cat

Abstract

The cervical vagus nerve (VN) was electrically stimulated in Nembutal-anaesthetized cats. The responses recorded from the cerebellar surface were found in lob. V and VI in a bilateral sagittal strip perpendicular to the longitudinal axis of the folia. At a longer latency, potentials were also found in the paramedian lobule. Field potential analysis confirmed the existence of a sagittal strip in the deep parts of the lobules. The distribution of these potentials and their field potential profiles indicate that they are transmitted through the climbing fiber (CF) system. Experiments with local anaesthetics and deafferentation support our view that the potentials described in the vermis by Dell and Olson (1951) could be originated extracerebellarly. A strong parallelism was found between the amplitude of the cerebellar responses and the amplitude of the group B₁ component of the vagal afferent potentials, having a conduction velocity between 4 and 20 m/s. The pathway by which the vagal afferents reach the inferior olive and the functional significance of these afferents are discussed.