Hearing depends on extracting frequency, intensity, and temporal properties from sound to generate an auditory map for acoustical signal processing. How physiology intersects with molecular specification to fine tune the developing properties of the auditory system that enable these aspects remains unclear. We made a novel conditional deletion model that eliminates the transcription factor NEUROD1 exclusively in the ear. These mice (both sexes) develop a truncated frequency range with no neuroanatomically recognizable mapping of spiral ganglion neurons onto distinct locations in the cochlea nor a cochleotopic map presenting topographically discrete projections to the cochlear nuclei. The disorganized primary cochleotopic map alters tuning properties of the inferior colliculus units, which display abnormal frequency, intensity, and temporal sound coding. At the behavioral level, animals show alterations in the acoustic startle response, consistent with altered neuroanatomical and physiological properties. We demonstrate that absence of the primary afferent topology during embryonic development leads to dysfunctional tonotopy of the auditory system. Such effects have never been investigated in other sensory systems because of the lack of comparable single gene mutation models.SIGNIFICANCE STATEMENT All sensory systems form a topographical map of neuronal projections from peripheral sensory organs to the brain. Neuronal projections in the auditory pathway are cochleotopically organized, providing a tonotopic map of sound frequencies. Primary sensory maps typically arise by molecular cues, requiring physiological refinements. Past work has demonstrated physiologic plasticity in many senses without ever molecularly undoing the specific mapping of an entire primary sensory projection. We genetically manipulated primary auditory neurons to generate a scrambled cochleotopic projection. Eliminating tonotopic representation to auditory nuclei demonstrates the inability of physiological processes to restore a tonotopic presentation of sound in the midbrain. Our data provide the first insights into the limits of physiology-mediated brainstem plasticity during the development of the auditory system.

• Klíčová slova
• Neurod1 mutation, auditory pathway, cochlear nucleus, inferior colliculus, plasticity, sensory topographical map,
• MeSH
• chování zvířat fyziologie   MeSH
• colliculus inferior anatomie a histologie   fyziologie   MeSH
• ganglion spirale cytologie   fyziologie   MeSH
• mapování mozku MeSH
• mezencefalon embryologie   fyziologie   MeSH
• myši knockoutované MeSH
• myši MeSH
• nucleus cochlearis anatomie a histologie   fyziologie   MeSH
• sluch fyziologie   MeSH
• sluchová percepce genetika   fyziologie   MeSH
• těhotenství MeSH
• transkripční faktory bHLH genetika   fyziologie   MeSH
• úleková reakce genetika   fyziologie   MeSH
• vestibulární aparát anatomie a histologie   fyziologie   MeSH
• vnímání výšky zvuku fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• Neurod1 protein, mouse MeSH Prohlížeč
• transkripční faktory bHLH MeSH

There is a long-lasting question of how distortion products (DPs) arising from nonlinear amplification processes in the cochlea are transmitted from their generation sites to the stapes. Two hypotheses have been proposed: (1) the slow-wave hypothesis whereby transmission is via the transverse pressure difference across the cochlear partition and (2) the fast-wave hypothesis proposing transmission via longitudinal compression waves. Ren with co-workers have addressed this topic experimentally by measuring the spatial vibration pattern of the basilar membrane (BM) in response to two tones of frequency f(1) and f(2). They interpreted the observed negative phase slopes of the stationary BM vibrations at the cubic distortion frequency f(DP) = 2f(1) - f(2) as evidence for the fast-wave hypothesis. Here, using a physically based model, it is shown that their phase data is actually in accordance with the slow-wave hypothesis. The analysis is based on a frequency-domain formulation of the two-dimensional motion equation of a nonlinear hydrodynamic cochlea model. Application of the analysis to their experimental data suggests that the measurement sites of negative phase slope were located at or apical to the DP generation sites. Therefore, current experimental and theoretical evidence supports the slow-wave hypothesis. Nevertheless, the analysis does not allow rejection of the fast-wave hypothesis.

• MeSH
• biologické modely MeSH
• deformace percepce fyziologie   MeSH
• Fourierova analýza MeSH
• interferometrie metody   MeSH
• kochlea fyziologie   MeSH
• lasery MeSH
• lidé MeSH
• otoakustické emise spontánní fyziologie   MeSH
• vibrace MeSH
• vnímání výšky zvuku fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

With the aim of characterizing the loss of high frequency hearing sensitivity in children, hearing thresholds and otoacoustic emissions were measured in a group of 126 normal hearing children and adolescents aged from 6 to 25 years. The subjects were divided into four 5-year age groups. Hearing thresholds over a range of 125 Hz-12.5 kHz were similar in all age groups, the average hearing threshold at 16 kHz was significantly elevated in the oldest age group. The response values of transiently evoked otoacoustic emissions (TEOAEs) significantly declined with age; the decline was negatively correlated with the hearing loss at 16 kHz. Significantly larger TEOAE responses and average distortion-product otoacoustic emission (DPOAE) values at 6.3 kHz were present in the youngest group in comparison with the other three older groups. Spontaneous otoacoustic emissions (SOAEs) were present in 70.8% of the children (in either one or both ears) with the greatest prevalence in the 11-20-year-old subjects. In the 21-25-year-old group, the hearing loss at 16 kHz was significantly smaller in ears with SOAEs than in ears without SOAEs. The results demonstrate that the increase in the high frequency hearing threshold at 16 kHz, which starts at ages over 20 years, is correlated with a decrease in the TEOAE responses at middle frequencies.

• MeSH
• akustické impedanční testy MeSH
• audiometrie čistými tóny MeSH
• dítě MeSH
• dospělí MeSH
• kochlea fyziologie   MeSH
• lidé MeSH
• mladiství MeSH
• otoakustické emise spontánní fyziologie   MeSH
• otoskopie MeSH
• sluchový práh fyziologie   MeSH
• věkové faktory MeSH
• vnímání výšky zvuku fyziologie   MeSH
• vysokofrekvenční nedoslýchavost patofyziologie   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Thresholds for triggering summed auditory evoked responses (ERs) were measured in non-auditory (= extralemniscal--EL) nuclei receiving direct auditory projections from the lateral lemniscus. Primary EL ERs with onset latency of 3-6 ms reflecting activation of direct EL projections of lemniscal auditory nuclei were registered in caudal pontine reticular nucleus (CPRN), in deep layers of superior colliculus (SC) and in ventromedial hypothalamus (VMH). Secondary EL ERs (waves of EL ERs with onset latency above 10 ms) reflecting diffuse auditory EL co-activation of the brain, were registered besides the above mentioned nuclei also in the medial amygdala (MA). Threshold sound intensities for evoking primary EL ERs in CPRN, SC and VMH, for secondary EL ERs in all extralemniscal nuclei tested, and for conditioned avoidance behavior in a two-way shuttle box, were compared mutually. There were no significant mutual differences among thresholds for inducing secondary EL ERs in all EL nuclei tested. Thresholds for evoking secondary EL ERs were lower than those for evoking primary EL ERs in deep layers of the SC, equaled to thresholds for primary EL ERs in the VMH and were higher than thresholds for primary EL ERs in the CPRN. The results suggest that auditory EL projections into SC and/or VMH (but not into CPRN) might represent the primary triggering source for secondary EL ERs in various extralemniscal nuclei. Although conditioning lowered the threshold intensities for inducing secondary EL ERs, the threshold sound intensity for triggering conditioned behavior was lower than the threshold for secondary EL ERs.(ABSTRACT TRUNCATED AT 250 WORDS)

• MeSH
• krysa rodu Rattus MeSH
• mapování mozku MeSH
• mezencefalon fyziologie   MeSH
• nervus vestibulocochlearis fyziologie   MeSH
• pons fyziologie   MeSH
• reakční čas fyziologie   MeSH
• retikulární formace fyziologie   MeSH
• sluchová dráha fyziologie   MeSH
• sluchová percepce fyziologie   MeSH
• sluchové evokované potenciály fyziologie   MeSH
• sluchový práh fyziologie   MeSH
• vnímání hlasitosti fyziologie   MeSH
• vnímání výšky zvuku fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• afázie diagnóza   patofyziologie   MeSH
• dítě MeSH
• dysartrie diagnóza   patofyziologie   MeSH
• lidé MeSH
• mozkový kmen patofyziologie   MeSH
• percepce řeči fyziologie   MeSH
• předškolní dítě MeSH
• reakční čas fyziologie   MeSH
• sluchové kmenové evokované potenciály fyziologie   MeSH
• vnímání výšky zvuku fyziologie   MeSH
• vývojové poruchy řeči diagnóza   patofyziologie   MeSH
• zvuková spektrografie MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Singing is generally known to be associated with lengthening of vocal ligaments and increasing frequency. At the same time, the anterior vibrating part of both the vocal ligaments become shortened. No explanation based on anatomical grounds has so far been given accounting for this phenomenon and its mechanism. The present paper advocates the crucial role of the elastic fibres (conus elasticus) connecting the upper edge of the cricoid cartilage with the vocal ligament on the circumference in the function of the speech organ pitch mechanism. The vocal ligament is a thickened free cranial margin of this part of the fibroelastic membrane. As the anterior arcus of the cricoid cartilage is approaching the midline of the thyroid cartilage during pitch production the elastic fibres are slackened in their front parts and stretched in their posterior parts, while the vocal ligaments are being stretched. This results in fixation of the posterior node point of the anterior vibrating vocal cord portion and inhibition of their posterior part.

• MeSH
• hlas fyziologie   MeSH
• lidé MeSH
• řeč fyziologie   MeSH
• vnímání výšky zvuku fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH