Zones in the cerebellar cortex: the adventures of one participant in the unfolding story.

Prior to the late 1960s, a variety of studies suggested that a general zonal pattern existed within the cerebellar cortex. The hypothesis proposed by Voogd, based on the organization of the subcortical white matter, indicated that this pattern may be very detailed, and he noted that "a further analysis of the corticonuclear projection is still necessary." This brief paper chronicles the approach used by the author to formulate a plan, initiate a large series of experiments (over 250), and follow the sometimes confusing results to finally arrive at an understanding of the details of cerebellar corticonuclear projections. It was discovered that a series of mediolateral cortical zones were present that were topographically related to the underlying cerebellar nuclei, and within each zone, the cortex projected in a rostrocaudal sequence to a specific cerebellar nucleus. The hypothesis proposed by Voogd was fundamentally proven.