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Sensory pathways, motor pathways, sensory-motor pathways, reflex arc, stimulus, pain. The reflex arc is a neural circuit made up of 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. The zoom at the bottom right of the illustration shows a motor neuron. Motor neurons are cells that control the movement of the body. They are represented by the purple cell that runs from the spinal cord to the muscle fibers where they transmit information from the brain. (Photo by: JACOPIN/BSIP/Universal Images Group via Getty Images)