Graphic representation that describes the circadian phase shifting response to a time cue (e.g., light) as a function of the internal circadian time at which the cue is presented.

Rapid-Eye Movement (REM) sleep is an ordinary sleep period with well-defined features of frequency and amplitudes of brain waves on electroencephalography (EEG). REM sleep is characterized by a loss of generalized muscle tone (atonia). The absence of atonia during REM sleep, called REM Sleep without Atonia (RSWA), is defined as a pathologic condition and indicates REM sleep behavior disorder (RBD).