Music on the brain

Music has an indisputable ability to trigger powerful emotions. It is frequently associated with memories of the past, and hearing just a short clip of a song can often trigger feelings from deep within the subconscious. It is also used in various therapies, can add considerable depth to a movie or film clip, and can have a substantial effect on your mood, even the first time you hear a song. What is it about music that conjures up such feelings?