Reflex arc, sensory-motor pathways, sensory pathways, motor pathways, stimulus, pain. The reflex arc is a neural circuit formed by a neuron receiving information and a neuron which induces an adapted action. This first neuron, or a chain of intermediate neurons are called afferent neurons or sensory neurons. They process the information received (interneurons). Here, the child pricks his hand on the cactus. The brain processes information. Then, the efferent neurons or motor neurons send the order to the effector organ (here the muscles of the arm and hand) after processing this information. In this case, the child will withdraw his hand from the spikes of the cactus.