title: Across-channel timing differences as a potential code for the frequency of pure tones.
abstract: When a pure tone or low-numbered harmonic is presented to a listener, the resulting travelling wave in the cochlea slows down at the portion of the basilar membrane (BM) tuned to the input frequency due to the filtering properties of the BM. This slowing is reflected in the phase of the response of neurons across the auditory nerve (AN) array. It has been suggested that the auditory system exploits these across-channel timing differences to encode the pitch of both pure tones and resolved harmonics in complex tones. Here, we report a quantitative analysis of previously published data on the response of guinea pig AN fibres, of a range of characteristic frequencies, to pure tones of different frequencies and levels. We conclude that although the use of across-channel timing cues provides an a priori attractive and plausible means of encoding pitch, many of the most obvious metrics for using that cue produce pitch estimates that are strongly influenced by the overall level and therefore are unlikely to provide a straightforward means for encoding the pitch of pure tones.
authors.affiliation: MRC Cognition & Brain Sciences Unit, 15 Chaucer Rd., Cambridge, CB2 7EF, UK. bob.carlyon@mrc-cbu.cam.ac.uk.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Carlyon
authors.affiliation: MRC Cognition & Brain Sciences Unit, 15 Chaucer Rd., Cambridge, CB2 7EF, UK.|Cochlear Ltd., 13059 E. Peakview Avenue, Centennial, CO, 80111, USA.|Department of Speech, Language, and Hearing Sciences, University of Colorado, Boulder, CO, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Long
authors.affiliation: Department of Psychology, University of Minnesota, 75 East River Rd., Minneapolis, MN, 55455, USA.
authors.forename: Christophe
authors.initials: C
authors.lastname: Micheyl
mesh_terms: D000818:Animals; D003056:Cochlear Nerve / Q000502:physiology*; D006168:Guinea Pigs; D010898:Pitch Perception / Q000502:physiology*; D013997:Time Factors