Cerebellar efferent fibers around the dentate nucleus. Pathological anatomy in olivo-ponto-cerebellar and dentato-pallido-luysian atrophy.

In patients with olivo-ponto-cerebellar atrophy (OPCA), the deep cerebellar white matter showed evidence of severe degeneration and gliosis. However, the circumferential white matter enclosing the dentate nucleus was less involved. In addition, the Holzer stain verified the presence of mild gliosis inside the wrinkled band of the dentate gray matter. In contrast, dentato-rubro-pallido-luysian atrophy (DRPLA) affected the mantle layer covering the dentate nucleus. The fibers encircling the dentate nucleus, which degenerate in DRPLA and are spared in OPCA, are anatomically noticeable to be dentatofugal pathways. Moreover, the afferent fibers from the cerebellar cortex and other systems may reach the dentate nucleus partly from the medial aspect via the hilus, as was noted in cases of OPCA.