Painful experiences from childhood and later in life, as well as traumatic events, seem to get locked in the nervous system with original images, sounds, thoughts, feelings, physical sensations and self-perceptions. These locked in experiences stored in the brain get triggered in the present when reminders occur. These reminders are current experiences which are similar to earlier experiences in some way. This triggering can create internal discomfort, which seems to come out of nowhere and is difficult to control. This can show up as inner tension, physical pain, painful memories, low self-esteem or unworthiness, and negative thoughts. Our way of functioning in the world, especially our sense of self-worth, how we relate to others, and how we react to different situations is related to this locked in material. The EMDR procedure seems to unlock the nervous system and allows the brain to reprocess these stored experiences, helping clients neutralize negative feelings and sensations, and thereby feel better about themselves and the past. It may be similar to what happens when we dream.
(adapted from Shapiro, 1995)