Conditioned reflex theory is the core of Pavlov's advanced neural activity theory, which refers to the temporary neural connection established between external stimulus and body response under certain conditions. Acquired, there are two forms of classical conditioned reflex and operational conditioned reflex. Unconditional reflection is the basis of conditioned reflection.

Conditioned reflex is also called feedforward control system in anatomy and physiology. Two things that were originally irrelevant, because they appeared together for a long time, and then one of them appeared, it was inevitable to associate with the other.

Conditioned reflex is acquired. It is a reflection established on the basis of unconditional reflection through certain conditions in the course of life. It is the basic regulation mode of higher nerve activity and the common physiological activity of human beings and animals. The basic condition of conditioned reflex is the combination of irrelevant stimulus and unconditional stimulus in time.

Any combination of irrelevant stimulus and unconditioned stimulus can form conditioned reflex, which is generally believed to be realized only with the participation of cerebral cortex. Traditionally, the establishment of conditioned reflex is due to multiple simultaneous excitations between the cortical representative area of conditioned stimulus and the cortical representative area of unconditioned stimulus, resulting in a "temporary connection" in function. The excitement caused by conditioned stimulus in the cortex can reach the cortical representative area of unconditioned reflex through temporary contact, thus causing a reaction that could not have been caused. The neural mechanism of temporary contact is not clear.

After the conditioned reflex is established, if the conditioned stimulus is used repeatedly without the reinforcement of unconditional stimulus, the conditioned reflex will fade. In the early stage of conditioned reflex formation, conditioned reflex also appeared the phenomenon of generalization and differentiation, which is the basis for the cerebral cortex to realize complex analysis and comprehensive functions.