Retrograde influence of surgical and chemical flocculectomy upon dorsal cap neurons of the inferior olive.

Retrograde influence of cerebellar cortical lesions upon neurons of the inferior olive was examined in albino rabbits after survival for 2 weeks. Ablation of the flocculus on one side induced a cell loss by 41% accompanied by a size reduction of as much as 27% in the contralateral dorsal cap, the source of climbing fiber afferents to the flocculus. By contrast, after destruction of flocculus Purkinje cells with local injections of 0.1% kainic acid-saline solution, there was no retrograde cell loss in the dorsal cap. However, a slight reduction in cell size (less than 10%) was noted.