EN
The mediolateral distribution of neurones of origin of the corticovestibular projections from the cerebellar posterior lobe in the rabbit was studied with the retrograde horseradish peroxidase (HRP) tracing method. After ionophoretic injections confined to various subdivisions of the vestibular nuclear complex (VNC), labelled Purkinje neurones were found ipsolaterally in widespreadmediolateral cortical regions of vermal lobules from VI to IX, as well as in crus I and crus II of the ansiform lobule, the copula pyramids, lobule HV and the ventral paraflocullus.However, when projections from individual sublobules were examined, a clesrly visible zonal pattern was found.Thus, Purkinje neurones projecting to VNC were arranged in longitudinal bands with madial and lateral boundaries quite well demarcated.these bands had a different distances from the midline.The present findings constitute the first indication of a zonal organization of corticovestibular projections from individual sublobules of the cerebellar postrior lobe in the rabbit.This zonal arragement of VNC afferents is discussed with the spacial emphasis on the cerebellar longitudinal zones related to previous studies on other species.