A neural representation of pitch salience in nonprimary human auditory cortex revealed with functional magnetic resonance imaging.
Pitch, one of the primary auditory percepts, is related to the temporal regularity or periodicity of a sound. Previous functional brain imaging work in humans has shown that the level of population neural activity in centers throughout the auditory system is related to the temporal regularity of a sound, suggesting a possible relationship to pitch. In the current study, functional magnetic resonance imaging was used to measure activation in response to harmonic tone complexes whose temporal regularity was identical, but whose pitch salience (or perceptual pitch strength) differed, across conditions. Cochlear nucleus, inferior colliculus, and primary auditory cortex did not show significant differences in activation level between conditions. Instead, a correlate of pitch salience was found in the neural activity levels of a small, spatially localized region of nonprimary auditory cortex, overlapping the anterolateral end of Heschl's gyrus. The present data contribute to converging evidence that anterior areas of nonprimary auditory cortex play an important role in processing pitch.