| Binaural sensitivity changes between cortical on and off responses. | |
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MedLine Citation:
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PMID: 21562191 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Neurons exhibiting on and off responses with different frequency tuning have previously been described in the primary auditory cortex (A1) of anesthetized and awake animals, but it is unknown whether other tuning properties, including sensitivity to binaural localization cues, also differ between on and off responses. We measured the sensitivity of A1 neurons in anesthetized ferrets to 1) interaural level differences (ILDs), using unmodulated broadband noise with varying ILDs and average binaural levels, and 2) interaural time delays (ITDs), using sinusoidally amplitude-modulated broadband noise with varying envelope ITDs. We also assessed fine-structure ITD sensitivity and frequency tuning, using pure-tone stimuli. Neurons most commonly responded to stimulus onset only, but purely off responses and on-off responses were also recorded. Of the units exhibiting significant binaural sensitivity nearly one-quarter showed binaural sensitivity in both on and off responses, but in almost all (∼97%) of these units the binaural tuning of the on responses differed significantly from that seen in the off responses. Moreover, averaged, normalized ILD and ITD tuning curves calculated from all units showing significant sensitivity to binaural cues indicated that on and off responses displayed different sensitivity patterns across the population. A principal component analysis of ITD response functions suggested a continuous cortical distribution of binaural sensitivity, rather than discrete response classes. Rather than reflecting a release from inhibition without any functional significance, we propose that binaural off responses may be important to cortical encoding of sound-source location. |
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Authors:
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Douglas E H Hartley; Johannes C Dahmen; Andrew J King; Jan W H Schnupp |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2011-05-11 |
Journal Detail:
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Title: Journal of neurophysiology Volume: 106 ISSN: 1522-1598 ISO Abbreviation: J. Neurophysiol. Publication Date: 2011 Jul |
Date Detail:
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Created Date: 2011-07-04 Completed Date: 2011-11-08 Revised Date: 2012-04-30 |
Medline Journal Info:
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Nlm Unique ID: 0375404 Medline TA: J Neurophysiol Country: United States |
Other Details:
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Languages: eng Pagination: 30-43 Citation Subset: IM |
Affiliation:
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Department of Physiology, Anatomy, and Genetics, Oxford University, Oxford, United Kingdom. douglas.hartley@dpag.ox.ac.uk |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Auditory Cortex / physiology* Auditory Pathways / physiology Auditory Perception / physiology* Ferrets / physiology Neurons / physiology Sound Localization / physiology |
| Grant Support | |
ID/Acronym/Agency:
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//Wellcome Trust |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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