<prompt> Which one of the following postural reflexesreaction requires intact coex?Tonic neck reflexNeck righting reflexMagnet reactionOptical righting reflex  <response>: Posture is regulated or acquired by reflex redistribution of tone in various muscle groups. Magnet reaction, also known as positive suppoing reaction, is seen in the spinal animal; Centre - Spinal cord Tonic neck reflex is seen in the decerebrate animal;Center - Vestibular nuclei. Neck righting reflex is seen in the midbrain or thalamic animal. Center - Midbrain nucleired nucleus. Optical righting reflex When a person is falling, the surrounding objects will be seen tilted; and, from this visual input the upright posture will be retained. Center - Visual coex. Thus, intact coex is required for this reaction. Postural Reflexes and their centres Reflexes Integrated in Stretch reflex Positive suppoing reaction Negative suppoing reaction Spinal cord Tonic labyrinthine and tonic neck reflexes Medulla Righting reflexes except optical righting reflexes Labyrinthine righting reflexes Neck righting reflexes Body on head righting reflexes Body on body righting reflexes Midbrain Conditioned reflex Optical righting reflexes Hopping and placing reaction Coex 