This amazing study reminds me of Flowers for Algernon:
"...the researchers recorded the EEG of human participants while they were awake and instructed to classify spoken words as either animals or objects by pressing a button, using the right hand for animals and the left hand for objects. The procedure allowed Kouider and his colleagues to compute lateralized response preparations—a neural marker of response selection and preparation—by mapping each word category to a specific plan for movement in the brain. Once that process had become automatic, the researchers placed participants in a darkened room to recline comfortably with eyes closed and continue the word classification task as they drifted off to sleep.
"Once the participants were asleep, the testing continued but with an entirely new list of words to ensure that responses would require the extraction of word meaning rather than a simpler pairing between stimulus and response. The researchers' observations of brain activity showed that the participants continued to respond accurately, although more slowly, even as they lay completely motionless and unaware."
José L. Duarte
Social Psychology, Scientific Validity, and Research Methods.