Which of the following is NOT true of reflexes? They are involuntary. The simplest pathway by which they occur is a reflex arc. They must be integrated in the brain. They allow individuals to react to a stimulus very quickly. Solution Answer: They must be intergrated in the brain. Explanation: A reflex is an involuntary and nearly instantaneous movement in response to a stimulus. Scientific use of the term \"reflex\" refers to a behavior that is mediated via the reflex arc. A reflex arc is a neural pathway that controls a reflex action. In higher animals, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This characteristic allows reflex actions to occur relatively quickly by activating spinal motor neurons without the delay of routing signals through the brain, although the brain will receive sensory input while the reflex is carried out. Analysis of the signal takes place after action has been taken..