Even before they are able to talk, infants show remarkable musical abilities that are similar to those of adults in that they are sensitive to musical scales and a regular tempo. Also, infants are able to differentiate between consonant and dissonant intervals. These perceptual skills indicate that music-specific predispositions exist.Prolonged exposure to music develops and refines these skills. Extensive musical training does not seem to be necessary in the processing of chords and keys. The development of musical competence most likely depends on the encoding of pitch along musical scales and maintaining a regular pulse, both of which are key components in the structure of music and aid in perception, memory, and performance. Also, the encoding of pitch and temporal regularity are both likely to be specialized for music processing. Pitch perception is absolutely crucial to processing music. The use of scales and the organization of scale tones around a central tone (called the tonic) assign particular importance to notes in the scale and cause non-scale notes to sound out of place. This enables the listener to ascertain when a wrong note is played. However, in individuals with amusia, this ability is either compromised or lost entirely.Music-specific neural networks exist in the brain for a variety of music-related tasks. It has been shown that Brocas area is involved in the processing of musical syntax.
While various causes of amusia exist, some general findings that provide insight to the brain mechanisms involved in music processing are discussed below. Pitch relations
Studies suggest that the analysis of pitch is primarily controlled by the right temporal region of the brain. The right secondary auditory cortex processes pitch change and manipulation of fine tunes; specifically, this region distinguishes the multiple pitches that characterize melodic tunes as contour (pitch direction) and interval (frequency ratio between successive notes) information. The right superior temporal gyrus recruits and evaluates contour information, while both right and left temporal regions recruit and evaluate interval information. In addition, the right anterolateral part of Heschls gyrus (primary auditory cortex) is also concerned with processing pitch information. Temporal relations
The brain analyzes the temporal (rhythmic) components of music in two ways: (1) it segments the ongoing sequences of music into temporal events based on duration, and (2) it groups those temporal events to understand the underlying beat to music. Studies on rhythmic discrimination reveal that the right temporal auditory cortex is responsible for temporal segmenting, and the left temporal auditory cortex is responsible for temporal grouping. Other studies suggest the participation of motor cortical areas in rhythm perception and production. Therefore, a lack of involvement and networking between bilateral temporal cortices and neural motor centers may contribute to both congenital and acquired amusia. Memory
Memory is required in order to process and integrate both melodic and rhythmic aspects of music.