Locke Cogito Dream Dotto

In the cogito argument, Descartes said,"I think, therefore, I am." In book II, Locke starts to talk about ideas, perception, and retention. He says we get these interpretations from our senses and experiences. He also says that there is nothing beyond the conscious mind, which I do not agree with. Although our dreams are based on actual occurances, how would Locke explain the events and abnormal occurances in our dreams if there was no unconscious part of our mind? For example, latent learning is unconsciously formed and can often show up in our dreams. However is imagination limited to our experiences?