A reflex arc is a neural pathway that controls a reflex action. In a simple spinal reflex, the pathway for an impulse is along a sensory neuron directly to a motor neuron through an interneuron because an interneuron enables communications (i.e a pathway for information passage) between a sensory neuron and motor neuron. They play vital roles in reflex actions, neuronal oscillations, neurogenesis in an adult mammalian vertebrate brain.