Dear List,
I am curious if you could recommend some reading for me. We have been increasingly interested in ITD coding with cochlear implants and have developed a nice little animal model which shows a surprisingly robust behavioral ITD sensitivity even if deafened in infancy and only implanted in young adulthood.
One question we often get and which we would like to investigate is: how much does it matter if there is a bit of a mismatch between the frequency channels in the left and right ears? How badly do they have to be mismatched before ITD sensitivity disappears?
I kind of assumed that there must have been a lot of psychoacoustics on this, at least in normally hearing human subjects. Of course at low frequencies, if you mismatch the left and right ears you get binaural beats, but what about envelope ITDs? You could deliver for example trains of short gabor clicks to each ear with a greater or lesser extent of carrier frequency mismatch, and see how the mismatch affects ITD thresholds. It seems like such an obvious thing to try, surely somebody must have done this or something similar? But a quick look on google scholar didn't yield very much. A modelling paper by Bonham and Lewis 1999 was the top hit. I haven't seen much in the way of data. Surely I must be missing something...? Any suggestions for relevant reading gratefully accepted.
Best wishes,
Jan
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Prof Jan Schnupp
City University of Hong Kong
Dept. of Neuroscience