<prompt> Which cerebellar component would be abnormal in a degenerative disease that affected spinal sensory neurons?Purkinje cellsMossy fibersParallel fibersClimbing fibers  <response>: Ans. B. Mossy fibersSpinal input, such as from the spinocerebellar tracts, enters the cerebellum on the mossy fibers. The climbing fibers originate from the inferior olivary nucleus of the medulla the olivo-cerebellar tract. The other components are intrinsic to the cerebellum.Diagram of neural connections in the cerebellum. Plus and minus - signs indicate whether endings are excitatory or inhibitory. BC, basket cell; GC, Golgi cell; GR, granule cell; NC, cell in deep nucleus; PC, Purkinje cell. 