You train your dog, Atticus, to salivate at the sound of a b…

You train your dog, Atticus, to salivate at the sound of a bell. Then you ring the bell every 5 minutes and don’t follow the ringing with food for Atticus. He salivates less and less and finally stops salivating at all when the bell rings. But the next morning, when you ring the bell, Atticus salivates! What term is used to explain the reappearance of this response?