Methods and systems are provided to monitor bio-signals associated with one or more physiological structures of a subject, process the bio-signals to determine neural information, determine a current state of the subject based on the neural information, determine feedback to be provided to the subject based on the current state and a desired state, and/or to provide the feedback to the subject in order to modify the subject's current state to the desired state. The neural information may include validated neural indices relating to dynamic regulation of the monitored physiological structures via identifiable neural pathways and/or neural metrics quantified from such neural indices.