perseverate

Concise Oxford English Dictionary © 2008 Oxford University Press:
perseverate /pəˈsɛvəreɪt/

▶verb Psychology repeat or prolong an action, thought, or utterance after the stimulus that prompted it has ceased.

– derivatives
perseveration noun.

– origin early 20th cent.: from L. perseverat- ‘strictly abided by’, from perseverare (see persevere).