Latencies of click-evoked auditory responses in a harbor porpoise exceed the time interval between subsequent echolocation clicks

Funding: This project was funded by U.S. Office of Naval Research Grant Nos. N00014-18-1-2062 and N00014-20-1-2709. Most auditory evoked potential (AEP) studies in echolocating toothed whales measure neural responses to outgoing clicks and returning echoes using short-latency auditory brainstem resp...

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Bibliographic Details
Published in:The Journal of the Acoustical Society of America
Main Authors: Beedholm, K., Ladegaard, M., Madsen, P. T., Tyack, P. L.
Other Authors: University of St Andrews. Institute of Behavioural and Neural Sciences, University of St Andrews. School of Biology
Format: Article in Journal/Newspaper
Language:English
Published: 2023
Subjects:
MCC
QL
Online Access:https://hdl.handle.net/10023/28114
https://doi.org/10.1121/10.0017163
Description
Summary:Funding: This project was funded by U.S. Office of Naval Research Grant Nos. N00014-18-1-2062 and N00014-20-1-2709. Most auditory evoked potential (AEP) studies in echolocating toothed whales measure neural responses to outgoing clicks and returning echoes using short-latency auditory brainstem responses (ABRs) arising a few ms after acoustic stimuli. However, little is known about longer-latency cortical AEPs despite their relevance for understanding echo processing and auditory stream segregation. Here, we used a non-invasive AEP setup with low click repetition rates on a trained harbor porpoise to test the long-standing hypothesis that echo information from distant targets is completely processed before the next click is emitted. We reject this hypothesis by finding reliable click-related AEP peaks with latencies of 90 and 160 ms, which are longer than 99% of click intervals used by echolocating porpoises, demonstrating that some higher-order echo processing continues well after the next click emission even during slow clicking. We propose that some of the echo information, such as range to evasive prey, is used to guide vocal-motor responses within 50–100 ms, but that information used for discrimination and auditory scene analysis is processed more slowly, integrating information over many click-echo pairs. We conclude by showing theoretically that the identified long-latency AEPs may enable hearing sensitivity measurements at frequencies ten times lower than current ABR methods. Peer reviewed