Subthreshold resonance properties contribute to the efficient coding of auditory spatial cues.
Neurons in the medial superior olive (MSO) and lateral superior olive (LSO) of the auditory brainstem code for sound-source location in the horizontal plane, extracting interaural time differences (ITDs) from the stimulus fine structure and interaural level differences (ILDs) from the stimulus envelope. Here, we demonstrate a postsynaptic gradient in temporal processing properties across the presumed tonotopic axis; neurons in the MSO and the low-frequency limb of the LSO exhibit fast intrinsic electrical resonances and low input impedances, consistent with their processing of ITDs in the temporal fine structure. Neurons in the high-frequency limb of the LSO show low-pass electrical properties, indicating they are better suited to extracting information from the slower, modulated envelopes of sounds. Using a modeling approach, we assess ITD and ILD sensitivity of the neural filters to natural sounds, demonstrating that the transformation in temporal processing along the tonotopic axis contributes to efficient extraction of auditory spatial cues.
Center for Neural Science, New York University, New York, NY 10003;Institute for Theoretical Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany;
Michiel W H
MW
Remme
University College London Ear Institute, University College London, London WC1X 8EE, United Kingdom; and.
Roberta
R
Donato
Center for Neural Science, New York University, New York, NY 10003;University College London Ear Institute, University College London, London WC1X 8EE, United Kingdom; and.
Jason
J
Mikiel-Hunter
University College London Ear Institute, University College London, London WC1X 8EE, United Kingdom; and.
Jimena A
JA
Ballestero
University College London Ear Institute, University College London, London WC1X 8EE, United Kingdom; and.
Simon
S
Foster
Center for Neural Science, New York University, New York, NY 10003;Courant Institute of Mathematical Sciences, New York University, New York, NY 10012.
John
J
Rinzel
University College London Ear Institute, University College London, London WC1X 8EE, United Kingdom; and d.mcalpine@ucl.ac.uk.
David
D
McAlpine
D000161:Acoustic Stimulation; D000818:Animals; D001306:Auditory Pathways / Q000166:cytology / Q000502:physiology*; D003054:Cochlear Implants; D003463:Cues; D006168:Guinea Pigs; D008144:Loudness Perception / Q000502:physiology; D008959:Models, Neurological; D009622:Noise; D009847:Olivary Nucleus / Q000166:cytology / Q000502:physiology*; D018408:Patch-Clamp Techniques; D051381:Rats; D013017:Sound Localization / Q000502:physiology*; D013028:Space Perception / Q000502:physiology
auditory system; spatial listening; superior olivary nucleus