A method for recognizing awareness in a subject includes performing optical imaging on at least one cortical region of the brain of the subject. Optical imaging data are obtained over time measuring one or more hemodynamic parameters in the at least one cortical region of the subject's brain. An observed variation pattern is determined in the measured hemodynamic parameters, and the observed variation pattern is compared to one or more known variation patterns characteristic of awareness. Substantial similarity between the observed and known variation patterns signals awareness in the subject.