In this chapter we present a new approach to research in music perception allowing one to investigate how musical sound representations are formed in the human brain. By studying subjects' brain responses to unattended stimuli we can determine, for instance, whether neural circuits are more readily activated by musical sounds implicitly learned than by unfamiliar sounds even in non-musicians. Indeed, neuronal populations seem to respond more efficiently to pitch deviations within sound patterns following the rules of Western scale structure, rather than to deviations inside patterns artificially created. Moreover, neural circuits are selectively activated by mistunings inside tonal melodies or by out-of-key chords inside harmonic cadences even when attention is not directed towards the sounds. These data together suggest that incoming sounds are more efficiently processed when they match the neural templates derived from our musical culture. The existence of 'musical memories' in the auditory cortex that are effortlessly activated enabling us, e.g., to identify and recognize speech vs. music sounds can thus be postulated.