Gap detection in the European starling (Sturnus vulgaris)

Summary Gap-detection thresholds were determined for single units in the cochlear ganglion and in auditory nerve fibres of the starling from responses to two broad-band noise bursts separated by a temporal gap of between 0.4 and 204.8 ms. All 35 units showed a threshold within the range of gap sizes tested. The median minimum-detectable gap was 12.8 ms with the minimum being 1.6 ms. A multiple regression analysis revealed that the size of the minimum-detectable gap was not significantly correlated with the neuron's CF, with its sharpness of tuning as given by its bandwidth 10 dB above threshold, or with its Q_10dB value. Only the level of stimulation above the neuron's threshold showed a significant negative correlation with the size of the minimum-detectable gap. These results are discussed with respect to theoretical considerations of limits posed on temporal resolution by the characteristics of peripheral filters. These findings are also discussed in the context of the coding of gaps at different levels of the starling's auditory system and in relation to psychoacoustic results in the starling on gap detection and time resolution described by temporal modulation transfer functions.     

单频刺激声稳态诱发反应的可靠性研究

目的:通过测试正常听力青年男女的听觉多频稳态诱发反应ASSR和单频刺激声稳态诱发反应探求单频刺激声稳态诱发反应的可靠性。方法:选取32名64耳听力正常的青年人作为受试者,对其进行纯音听阈、ASSR及四个0.5、1、2、4k Hz单频刺激声稳态诱发反应阈值测试,并记录0.5、1、2和4k Hz四个频率纯音阈值及ASSR及四个单频刺激声稳态诱发反应阈值。结果:ASSR在0.5、1、2和4k Hz四个频率的反应阈值与纯音听阈阈值相关性系数分别为0.64、0.81、0.79、0.85;0.5k Hz单频刺激声稳态诱发反应阈值与ASSR阈值具有明显统计学差异,其余3个单频刺激声稳态诱发反应阈值与ASSR阈值没有统计学差异,0.5k Hz单频刺激声稳态诱发反应阈值与纯音听阈阈值相关性系数为0.81。结论:ASSR阈值与纯音听阈具有较好的相关性,0.5k Hz单频刺激声稳态诱发反应可以提高0.5k Hz ASSR阈值与纯音听阈的相关性。     

珠江三角洲陈村水道航道整治工程声环境影响分析

根据水道沿线周围地区的声环境质量现状,通过模式计算,对珠江三角洲陈村水道整治工程施工期和运行期间航道200m以内区域进行声环境影响预测与评价。施工期噪声在厂界以内基本符合标准,对周围环境造成的影响不大;营运期噪声对周围环境造成一定影响,噪声影响以林岳村最大,腰古农场最小,昼间等效声级最大为66.2dB(A),最小为63.5dB(A);夜间等效声级最大为58.8dB(A),最小为54dB(A),超标值昼间为5.8%～10.2%,夜间为8%～17.6%。     

Maps of interaural time difference in the chicken’s brainstem nucleus laminaris

Animals, including humans, use interaural time differences (ITDs) that arise from different sound path lengths to the two ears as a cue of horizontal sound source location. The nature of the neural code for ITD is still controversial. Current models differentiate between two population codes: either a map-like rate-place code of ITD along an array of neurons, consistent with a large body of data in the barn owl, or a population rate code, consistent with data from small mammals. Recently, it was proposed that these different codes reflect optimal coding strategies that depend on head size and sound frequency. The chicken makes an excellent test case of this proposal because its physical prerequisites are similar to small mammals, yet it shares a more recent common ancestry with the owl. We show here that, like in the barn owl, the brainstem nucleus laminaris in mature chickens displayed the major features of a place code of ITD. ITD was topographically represented in the maximal responses of neurons along each isofrequency band, covering approximately the contralateral acoustic hemisphere. Furthermore, the represented ITD range appeared to change with frequency, consistent with a pressure gradient receiver mechanism in the avian middle ear. At very low frequencies, below 400 Hz, maximal neural responses were symmetrically distributed around zero ITD and it remained unclear whether there was a topographic representation. These findings do not agree with the above predictions for optimal coding and thus revive the discussion as to what determines the neural coding strategies for ITDs.     

不同听力曲线分型突发性耳聋患者听阈水平及临床特征分析

摘要 目的：探讨不同听力曲线分型突发性耳聋患者听阈水平及临床特征分析。方法：前瞻性选取我院2019年10月至2022年10月我院收治的80例突发性耳聋患者作为研究对象。采集患者临床特征信息。检测所有患者听阈水平。采用秩和检验进行多组间差异分析;采用Spearman检验进行相关性分析;采用多元线性回归模型进行回归分析。结果：平坦下降组、低频下降组、高频下降组和全聋组在侧别、性别、糖尿病、耳鸣、眩晕、耳闷胀感亚组间差异显著（P<0.05）,而在年龄、高血压和脑梗塞亚组间无显著差异（P＞0.05）;平坦下降组、低频下降组、高频下降组和全聋组在极重度、重度、中度、轻度、正常亚组间差异显著（P<0.05）;突发性耳聋患者听力曲线分型与侧别、性别、糖尿病、耳鸣眩晕、耳闷胀感、听阈水平密切相关（P<0.05）,而与年龄、高血压、脑梗塞无关（P＞0.05）;多元线性回归结果显示,耳鸣、眩晕、耳闷胀感、听阈水平、侧别是影响突发性耳聋患者听力曲线分型的独立危险因素（P<0.05）。结论：突发性耳聋不同听力曲线分型患者间存在临床特征及听阈水平的差异,临床可依据患者独特疾病特征构建精准的治疗策略进行干预。     

Connexins 26 and 30 are co-assembled to form gap junctions in the cochlea of mice

The importance of connexins (Cxs) in the cochlear functions has been indicated by the finding that mutations in connexin genes cause a large proportion of sensorineural deafness cases. However, functional roles of connexins in the cochlea are still unclear. In this study, we compared the relative expression levels of 16 different subtypes of mouse connexins in the cochlea. cDNA macroarray hybridizations identified four most prominently expressed connexins (listed in descending order): Cxs 26, 29, 30, and 43. Two of these connexins (Cx26 and Cx30), both belonging to the beta-group, were investigated for their molecular assemblies in the cochlea. Co-immunostaining showed expressions of Cxs 26 and 30 in the same gap junction plaques and their co-assembly was confirmed by co-immunoprecipitation of proteins extracted from the cochlear tissues. The heterologous molecular assembly of connexins is expected to produce gap junctions with biophysical characteristics appropriate for maintaining ionic homeostasis in the cochlea.     

Directionality of the pressure-difference receiver ears in the northern leopard frog, Rana pipiens pipiens

We studied the directional response of the coupled-eardrum system in the northern leopard frog, Rana pipiens pipiens. Eardrum behavior closely approximates a linear time-invariant system, with a highly correlated input–output relationship between the eardrum pressure difference and the eardrum velocity. Variations in the eardrum transfer function at frequencies below 800 Hz indicate the existence of an extratympanic sound transmission pathway which can interfere with eardrum motions. The eardrum velocity was shown to shift in phase as a function of sound incident angle, which was a direct result of the phase-shift of the eardrum pressure difference. We used two laser-Doppler vibrometers to measure the interaural vibration time difference (IVTD) and the interaural vibration amplitude difference (IVAD) between the motions of the two eardrums. The coupled-eardrum system enhanced the IVTD and IVAD by a factor of 3 and 3 dB, respectively, when compared to an isolated-eardrum system of the same size. Our findings are consistent with the time-delay sensitivity of other coupled-eardrum systems such as those found in crickets and flies.     

Encoding of acoustic directional information by saccular afferents of the sleeper goby, Dormitator latifrons

This paper reports on directional response properties of saccular afferents of the sleeper goby, Dormitator latifrons, to 100-Hz acoustic particle motions with a focus on testing the hypothesis that the response directionality of a fish's auditory afferents derives from the morphological polarity of sensory hair cells in the otolithic organs. Spontaneous rates (SR) and best sensitivities (BS) of saccular afferents ranged from 0 to 162 spikes/sec and from 0.2- to 100-nm RMS displacement. SR did not vary with BS. Most saccular afferents were phase-locked to sinusoidal stimulation and had sustained temporal response patterns with some adaptation. All saccular afferents were directionally sensitive to the stimulus, and the sharpness of directional response curves was determined by a directionality index (DI). The DI ranged from 0.64 to 1.50 (mean=1.02, SE=0.02, n=100) and gradually decreased with stimulus level throughout afferents' response dynamic range. Many afferents had approximately symmetric directional response curves relative to their best response axes (BRA). BRA of most afferents remained constant with stimulus level. The BRA distribution had a peak along an axis that correlates closely with the morphological polarity of saccular hair cells. Therefore, our results strongly support the hypothesis. Accepted: 19 December 1997     

Acoustic Pollution in the Oceans: The Search for Legal Standards

The introduction of noise into the marine environment may have significant impacts on marine species and ecosystems. This article examines how the existing international legal framework can be used to address this issue. After providing some background information on sound in the marine environment, the relevant global and regional instruments dealing with the protection of the marine environment, marine pollution, and the conservation of marine species and ecosystems are discussed. The analysis suggests that international law already requires states to address various aspects of this issue. A number of instruments and institutions provide an adequate framework to prescribe rules and standards regarding most sources of acoustic pollution.