No Resolvable Spectral Cues

Pitch perception depends on two types of cues provided by acoustic stimuli: spectral cues arise from the tonotopic organization of the basilar membrane, while temporal cues are contained within the pattern of action potentials generated in auditory nerve fibers. Filtered iterated rippled noise (IRN) can be used to examine how adults and infants perceive stimuli without resolvable spectral cues. Chapter 2 uses event-related potentials (ERPs) to compare adult perception of IRN and complex harmonic stimuli. Functional imaging studies have revealed a common pitch centre along lateral Heschl’s gyrus, but lack the temporal resolution to index different stages of processing. Chapter 2 reveals differences between feature extraction-related ERP components elicited in response to different pitch-evoking stimuli. However, no differences were observed in the mismatch negativities (MMN), suggesting pitch percepts formed at this stage of processing are independent of stimulus type. Moreover, source estimates for the MMN were consistent with fMRI studies. Chapter 3 demonstrates that infants can perceive the pitch of stimul