Development of auditory phase-locked activity for music sounds.

Abstract

The auditory cortex undergoes anatomical and functional development that reflects specialization for learned sounds. Auditory maturation is evident in the transient auditory evoked potentials (AEPs) and auditory phase-locked oscillatory activity. Development of AEPs and the phase-locking strength of oscillatory auditory responses to piano, violin, and pure tones were examined. The hypothesis was that if oscillatory activity in different frequency bands reflects different aspects of sound processing, then the development of phase-locking at these frequencies will have different maturational trajectories. Phase-locking for theta (4–8 Hz), alpha (8–14 Hz), lower-to-mid-beta (14–25 Hz), and upper beta and gamma (25–70 Hz) bands strengthened with age and was stronger for musical than pure tones. The phase-locking increase for gamma and upper beta bands mainly reflected the maturation of the spectral representations for sounds. In contrast, increase in phase-locking for theta, alpha, and lower-to-mid-beta was mainly attributed to sensitivity to sound temporal onset rise time. Frequency-specific phase-locking provides a tool to assess auditory development for spectral and temporal aspects of naturalistic complex sounds. [This research was supported by grants from the Canadian Institutes of Health Research and the National Institutes of Health, National Institute on Deafness and other Communication Disorders.]