Current theories of auditory pitch perception propose that cochlear place (spectral) and activity timing pattern (temporal) information are somehow combined within the brain to produce holistic pitch percepts, yet the neural mechanisms for integrating these two kinds of information remain obscure. To examine this process in more detail, stimuli made up of three pure tones whose components are individually resolved by the peripheral auditory system, but that nonetheless elicit a holistic, "missing fundamental" pitch percept, were played to human listeners. A technique was used to separate neural timing activity related to individual components of the tone complexes from timing activity related to an emergent feature of the complex (the envelope), and the region of the tonotopic map where information could originate from was simultaneously restricted by masking noise. Pitch percepts were mirrored to a very high degree by a simple combination of component-related and envelope-related neural responses with similar timing that originate within higher-frequency regions of the tonotopic map where stimulus components interact. These results suggest a coding scheme for holistic pitches whereby limited regions of the tonotopic map (spectral places) carrying envelope- and component-related activity with similar timing patterns selectively provide a key source of neural pitch information. A similar mechanism of integration between local and emergent object properties may contribute to holistic percepts in a variety of sensory systems.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1838520 | PMC |
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0000369 | PLOS |
Sci Rep
January 2025
Department of ENT/Audiology & School for Mental Health and NeuroScience (MHENS), Maastricht University Medical Centre, Maastricht, The Netherlands.
Traditionally, the place-pitch 'tonotopically' organized auditory neural pathway was considered to be hard-wired. Cochlear implants restore hearing by arbitrarily mapping frequency-amplitude information. This study shows that recipients, after a long period of sound deprivation, preserve a level of auditory plasticity, enabling them to swiftly and concurrently learn speech understanding with two alternating, distinct frequency maps.
View Article and Find Full Text PDFJ Comp Neurol
December 2024
School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
A gene cadre orchestrates the normal development of sensory and non-sensory cells in the inner ear, segregating the cochlea with a distinct tonotopic sound frequency map, similar brain projection, and five vestibular end-organs. However, the role of genes driving the ear development is largely unknown. Here, we show double deletion of the Iroquois homeobox 3 and 5 transcription factors (Irx3/5 DKO) leads to the fusion of the saccule and the cochlear base.
View Article and Find Full Text PDFNat Neurosci
January 2025
Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland.
JAMA Otolaryngol Head Neck Surg
November 2024
Department of Otolaryngology-Head and Neck Surgery, University Hospital, Rennes, France.
Importance: Cochlear implants are an effective technique for enhancing speech perception abilities in quiet environments for people with severe to profound deafness. Nevertheless, complex sound signals perception, such as music perception, remains challenging for cochlear implant users.
Objective: To assess the benefit of a tonotopic map on music perception in new cochlear implant users.
Ear Hear
December 2024
Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine in St. Louis, St Louis, Missouri, USA.
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