[Dynamics of acetylcholinesterase activity in the brain during elaboration and stabilization of defensive conditioned reflexes].

Electro-defensive condtioned reflexes (CR) to light were elaborated in rats in Y-maze in one experimental session and their training was continued during subsequent 20 sessions. Immediately after CR elaboration or the 20th session of its training, AChE activity in the motor and visual cortex and the hippocampus decreased, increasing again in 24 hours. Animals used as active control which received non-paired photic and electric stimuli, exhibited opposite changes of AChE activity.