This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: AIIMS 2018, Subject name: Physiology
Fibers reaching directly to Purkinje cell of cerebellum arise from which of the following: 
Select and explain. 
A. Vestibular nucleus, B. Inferior olivary nucleus, C. Raphe nucleus, D. Locus ceruleus
B: Inferior olivary nucleus
Answer: B: Inferior olivary nucleus 
Explanation: Functional unit of cerebellum = Purkinje cell neuronal circuit of the Purkinje cell: - Afferent inputs of cerebellum Climbing fiber type Mossy fiber type Originate from inferior olives of the medulla. Enter cerebellum from multiple sources - cerebrum, brainstem &spinal cord. Send collaterals to excite deep nuclear cells & then proceed to synapse with granule cells. Output from - deep nuclear cell Excitatory influence from direct connection with cerebellum from the brain or periphery Inhibitory influence from Purkinje cell