In 1983 Libet showed that before subjects announced their decision to perform an action (and hence, or so Libet assumed, before deciding to perform an action) their motor cortex was already preparing the way for the act in question.
From "Libet was wrong...?" @Conscious Entitites
...Benjamin Libet’s remarkable experiments, which seemed to show that decisions to move were really made half a second before we were aware of having decided.
Anyway, the line I'm recommending here is what I take to be be one of Dan Dennett's key insights in his various discussions of Libet, so I don't pretend any originality here.