This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuroanatomy, Subject name: Anatomy
Climbing fibres arise from - 
Select and explain. 
A. Inferior olivary nucleus, B. Red nucleus, C. Caudate nucleus, D. Putamen
A: Inferior olivary nucleus
Answer: A: Inferior olivary nucleus 
Explanation: Ans. is 'a' i.e., Inferior olivary nucleus * Afferent for cerebellum comes through two fibers : climbing fibers and Mossy fibers.* Climbing fibers which brings information only from the inferior olivary nuclei and establish excitatory synapes with purkinje cells.* All other afferent input to the cerebellum is brought by the other types of fibers, called Mossy fibers which establish excitatory synapse with granule cells in the granular cell layer. The axon of granule cells, called parallelfibers, stimulate the purkinje cells. Thus mossy fibers, like the climbing fibers, also end up in stimulating the purkinje cells.