Listening to Music Engages a Wide Range of Brain Components
It was originally believed that music perception was specific to the right hemisphere of the brain. Evidence that has since coming to light through brain-imaging technology and lesion studies (in which conclusions are drawn about the function of specific parts of the brain based on the effect damage to that area has on human behavior) that has resulted in this model being discarded in favor of one that is much more complex. We now know that music engages both the left and right hemispheres as well as sub-cortical regions and the hindbrain. Because music is a complex stimulus with many elements, it is not processed in a single area of the brain. The various aspects of musical stimuli are processed by a number of localized brain regions. Components of music include rhythm, tempo (the rate of speed of a musical piece), harmony (the combination of simultaneous musical notes), pitch (the highness or lowness of sound), timbre (the quality of a sound due to its overtones—often distinct to an individual voice or instrument), contour (general form or structure), loudness, and melody (arrangement of successive sounds). When we listen to music, all of these brain regions process different aspects of the stimuli simultaneously to produce the overall effect that music has on humans.
This modular conception of music perception is supported by the fact that it is almost impossible to lose all aspects of music perception. Acquired amusia is the loss of musical ability due to a traumatic event such as brain damage. Symptoms of amusia are determined by the location and nature of the lesion, which indicates that a multiplicity of brain regions are responsible for processing different aspects of music. For example, amusiacs with lesions to the temporal/parietal regions of the left hemisphere tend to experience an inability to produce or conceive of rhythmic patterns, while damage to the left superior temporal gyrus disturbs the recognition and production of melodic sequences.