“Libet, however, draws attention to earlier work according to which a short (300-ms) period of appropriate cerebral activity is required to achieve the “neuronal adequacy” necessary for a conscious experience. He proposes that the same is true of the relationship between the readiness potential, RP, and the decision to act at about -200 ms. This suggests a third role, a more functionally epiphenomenal one, according to which the apparent conscious decision is neither a veto nor a trigger but merely the coming to consciousness of an unconscious process already in progress and indicated by the RP” (Libet, 1985, p.548).
Libet, B. (1985). Unconscious cerebral initiative and the role of conscious will in voluntary action. Behavioral and brain sciences, 8(4), 529-539.
Libet, B. (1999). Do we have free will?. Journal of consciousness studies, 6(8-9), 47-57.