Behavioral and physiological correlates of temporal pitch perception in electric and acoustic hearing.
In the "4-6" condition of experiment 1, normal-hearing (NH) listeners compared the pitch of a bandpass-filtered pulse train, whose inter-pulse intervals (IPIs) alternated between 4 and 6 ms, to that of isochronous pulse trains. Consistent with previous results obtained at a lower signal level, the pitch of the 4-6 stimulus corresponded to that of an isochronous pulse train having a period of 5.7 ms-longer than the mean IPI of 5 ms. In other conditions the IPI alternated between 3.5-5.5 and 4.5-6.5 ms. Experiment 2 was similar but presented electric pulse trains to one channel of a cochlear implant. In both cases, as overall IPI increased, the pitch of the alternating-interval stimulus approached that of an isochronous train having a period equal to the mean IPI. Experiment 3 measured compound action potentials (CAPs) to alternating-interval stimuli in guinea pigs and in NH listeners. The CAPs to pulses occurring after 4-ms intervals were smaller than responses to pulses occurring after 6-ms intervals, resulting in a modulated pattern that was independent of overall level. The results are compared to the predictions of a simple model incorporating auditory-nerve (AN) refractoriness, and where pitch is estimated from first-order intervals in the AN response.
Carlyon
Robert P
RP
MRC Cognition & Brain Sciences Unit, 15 Chaucer Road, Cambridge CB2 7EF, United Kingdom. bob.carlyon@mrc-cbu.cam.ac.uk
Mahendran
Suresh
S
Deeks
John M
JM
Long
Christopher J
CJ
Axon
Patrick
P
Baguley
David
D
Bleeck
Stefan
S
Winter
Ian M
IM
D000161:Acoustic Stimulation / Q000523:psychology*; D000200:Action Potentials; D000818:Animals; D003054:Cochlear Implants; D003056:Cochlear Nerve / Q000502:physiology*; D003463:Cues; D006168:Guinea Pigs; D006801:Humans; D008959:Models, Neurological; D010897:Pitch Discrimination / Q000502:physiology*; D011571:Psychoacoustics; D012032:Refractory Period, Electrophysiological