perseveration

(countable, uncountable) An uncontrollable repetition of a particular response, such as a word, phrase, or gesture, despite the absence or cessation of a stimulus, usually caused by a brain injury or other organic disorder.
(countable, uncountable) The tendency to continue or repeat an act or activity after the cessation of the original stimulus.
(countable, uncountable) The act or an instance of persevering; perseverance.
(countable, derogatory, uncountable) An argument by repetition; a mantra.