耳蜗电位的持续反应与其中单个脉冲的反应

研究了豚鼠耳蜗电位中持续反应与其中的单个脉冲反应的关系。由于听学系统存在着非线性,因此仅仅知道由单个短声诱发的耳蜗电位脉冲反应还无法预测一串等间隔重复短声诱发的持续反应。然而,等间隔重复短声串中第5个以后的每个短声受前面所有短声的掩蔽都相同,诱发的反应都相同,因此持续反应的稳态部分可以由掩蔽作用达到饱和时单个短声的反应通过延时相加得到。本文在时间域和频率域上定量地证明了这点。     

听觉诱发电位早成分中掩蔽作用与刺激参数之间的关系

本文研究了用短声串作为刺激时,其中每个短声所诱发的反应所受到的掩蔽作用与其前短声的个数、间距以及强度之间的关系.实验表明,个数越多,掩蔽作用越强,但当个数大到一定数目时,所受掩蔽作用渐趋饱和,不再随个数的增大而增大;间距越小,掩蔽作用越强;强度越大,掩蔽作用也越强     

听神经复合动作电位适应性的定量研究

本文研究了短声串作为刺激时,听神经复合动作电位(CAP)中发生的掩蔽作用随短声串的各项参数变化的关系.结果表明:①双短声诱发的CAP中掩蔽作用随两个短声间距的增大而减小;②掩蔽声越强,或被掩蔽声越弱,掩蔽作用越明显.恢复所需的时间也越长;③掩蔽作用随掩蔽声个数的增多而增大,当个数增大到一定数目时,掩蔽作用趋于饱和.     

脑干对谐波复合音反应中的基频成分与早期听觉信息处理

研究了以２００Ｈｚ为基频的谐波复合音诱发的持续性脑干听觉诱发电位。分析了刺激信号中各种参数的改变对诱发电位的影响。发现：１．不含基频的谐波复合音,其诱发反应频谱上除出现与刺激组分相对应的频率成分外,还出现基频成分及其它谐波成分。２．由高次谐波组成的三组分谐波复合音诱发的反应对各刺激组分相位结构有较大敏感性,而低次谐波组成的三组分谐波复合音诱发的反应对相位结构的敏感性较差。３．对双组分谐波复合音,无论其间差频等于基频或基频的两倍,其诱发反应频谱中均出现基频成分。     

后掩蔽效应对大棕蝠下丘神经元声反应的影响

以回声定位蝙蝠为模式动物,采用在体动物细胞外单位记录法,研究了后掩蔽效应对下丘神经元声反应的影响。结果显示,部分神经元(38％,12／31)对测试声刺激的反应明显受到掩蔽声的抑制,其后掩蔽效应强弱与掩蔽声和测试声的相对强度差(inter-stimulus level difference,SLD),以及测试声与掩蔽声之间的间隔时间(inter-stimulus onset asynchrony,SOA)有关：当掩蔽声强度升高或测试声强度降低时,后掩蔽效应增强;而SOA的缩短,亦可见后掩蔽效应增强。另外,相当数量的神经元(52%,16／31)对测试声刺激的反应并不受掩蔽声的影响,其中有的神经元只有在特定SLD和SOA时,才表现出后掩蔽效应。而少数下丘神经元(10％,3／31)在特定SLD和SOA时,掩蔽声对测试声反应有易化作用。上述结果表明,部分下丘神经元参与了声认知活动中的后掩蔽形成过程,推测下丘神经元在定型声反应特性中,对掩蔽声诱导的兴奋前抑制性输入与测试声诱导的兴奋性输入之间的时相性动态整合起关键作用。     

刺激丘脑体感觉核引起的皮层诱发电位和胼胝体电位的相互作用

用刺激兔丘脑后腹核引起的皮层诱发电位作为制约反应,胼胝体电位作为测验反应,可见到后者发生先抑制后易化的改变。易化过程表现为测验反应慢成分幅度的增大和其后发放活动的增强,而快成分却只受到抑制。如制约反应具有后发放活动,则测验反应幅度将伴有相应的周期性波动。如果,被后腹核刺激引起的诱发电位作用而增大的胼胝体电位,反过来再作用于后腹核刺激引起的诱发电位,则可见到其有强大的胼胝体易化作用,同时胼胝体电位慢成分幅度愈大,其胼胝体易化作用也愈强,两者有正比关系。     

诱发性耳声发射的掩蔽

３４例听觉正常受试者（共４８耳）进行疏波短声诱发性耳声发射（ＥＯＡＥ）掩蔽实验,项目包括同侧同时掩蔽、同侧后掩蔽和对倒后掩蔽。同时掩蔽的掩蔽声是稳态白噪声,后掩蔽的掩蔽声是宽带噪声。同侧同时掩蔽强度达３０ｄＢＳＬ时,未观察到对ＥＯＡＥ的掩蔽效应,但对主观听觉感受有掩蔽作用,表明ＥＯＡＥ的客观属性反映听觉行为有其局限性、同侧及对侧后掩蔽出现掩蔽效应时的掩蔽强度分别为３０和５０ｄＢＳＬ,掩蔽阈约分别为５９和６８ｄＢＳＬ。耳蜗的机械特性－非线性或耳蜗内存在的某种功能性的反馈调节系统可能是同侧后掩蔽的作用机理。下行的对侧橄榄耳蜗内侧束对外毛细胞主动收缩的抑制性作用,可有效解释对倒后掩蔽的ＥＯＡＥ变化。     

蟾蜍延脑听中枢的单位电反应的一些观察

我们利用电生理学的方法测定了蟾蜍延脑听反应的区域,并研究了延脑听神经元对短声及纯音的反应特性。结果表明:1.从内耳来的传入冲动主要是向同侧的延脑听区传递的。2.蟾蜍听觉系统感受的频率范围在4,000周/秒以下,对于500—600周/秒以及1,000—1,200周/秒的频率最为敏感。多数听神经元的反应阈值在人听阈上25—35分贝左右。少数在人听阈上5—10分贝或45—55分贝。3.根据短声及特征频率的纯音所引起的反应,可将延脑听神经元的反应分为长潜伏期(平均约12毫秒)及短潜伏期(平均约3毫秒)两种形式。反应潜伏期的长短,可能是由不同类型的神经元的特性所决定的,但在同一神经元,在改变声音刺激的频率或强度时,反应的潜伏期也有变化。4.延脑听神经元对纯音刺激的反应有连续发放的、给声的、给-撤声的以及撤声的几种形式。其中以连续发放的反应形式最为常见。5.有时,纯音引起的连续发放是迭加在振幅达十几毫伏的正相慢波之上的,发放的波形为正单相锋形电位,它的上升相较陡,下降相缓慢。短声也可以引起这样的锋形电位,它们可能是细胞内记录到的反应。     

广义时频分析方法在耳声发射研究中的应用Ⅱ.短声与短纯音诱发耳声发射信号的时频分布

为了进一步探讨耳声发射的产生机制,需要研究不同类型刺激诱发的耳声发射之间的相互关系.主要研究短声与短纯音诱发的耳声发射,用广义时频分析方法中的锥形核分布分别计算了它们的时频分布,从其时频分布分析了它们之间的相互关系.结果表明:具有不同中心频率的短纯音刺激诱发耳声发射的时频分布的迭加与短声刺激诱发的耳声发射的时频分布具有相似性,两者时频分布中的主要频率成分数目、潜伏期和持续时间完全相同,它们高度的相关性支持了短声与短纯音诱发的耳声发射具有共同的产生器的观点.     

不同时程弱前掩蔽声对小鼠下丘神经元声反应的选择性抑制

自由声场条件下,以强度为神经元最小阈值阈上5dB,时程分别为40、60、80和100ms的纯音作为前掩蔽声,观察和记录了不同时程弱前掩蔽声对小鼠（Musmusculus Km）下丘神经元发放和声强处理的影响。实验记录到154个神经元,对其中的104个神经元做了不同时程掩蔽声影响的测试。结果发现：掩蔽声对神经元放电率的抑制作用在时间上表现为前抑制（41％）、后抑制（9％）和全抑制（50％）三种类型。改变掩蔽声时程时,大部分神经元（72％）的抑制类型不发生改变,但少部分神经元（28％）随掩蔽声时程的增加,大量的后抑制类型转变为前抑制或全抑制类型。此外,超过一半的神经元（58．06％）其强度．放电率函数曲线随掩蔽声时程的改变而发生转变,主要表现为单调型向饱和型转变及饱和型向非单调型转变,这种转变并不随掩蔽声时程增加表现出规律性的变化。结果表明,前掩蔽作用于下丘神经元声反应的时间域和强度域时具有不均衡性,推测不同时程弱前掩蔽声激活的抑制性输入能分化性调制下丘神经元声反应特性。     

有关猫听觉脑干电反应（ABR）两耳干涉作用的研究

用不同声强稳态白噪声和短声同时分别刺激两耳,观察白噪声负荷侧耳蜗破坏前后另一侧ＡＢＲ的改变,探讨两耳干涉作用及其可能的机制。结果显示,对侧耳蜗破坏前,４０ｄＢ和７５ｄＢ白噪声对０ｄＢ、４５ｄＢ、７０ｄＢ和７５ｄＢＳＰＬ的短声诱发的ＡＢＲ各波振幅均有明显影响（Ｐ＜０．０５０．０１）。耳蜗破坏后,同样条件下记录的ＡＢＲ振幅基本无明显变化（Ｐ＞０．０５）。提示白噪声对短声有一定的干涉作用。短声为７０ｄＢＳＰＬ时ＡＢＲＰ１波振幅的减小可能与中枢离中控制相关。     

Single unit activity related to acoustic stimulus meaning in the cat auditory cortex during instrumental food reflex

Responses of 93 neurons to isolated presentation of a single click and a series of 10 clicks with following frequency of 1000 Hz and responses of 66 neurons after the click had become a positive conditioned stimulus, and a series of 10 clicks had become a differential, negative stimulus, were investigated in chronic experiments on cats. Formation and realization of differential inhibition of an instrumental food reflex was shown not to lead to strengthening of inhibition in the auditory cortex, and the process of differential inhibition itself within the primary auditory cortex is not essentially an inhibitory process. Identical changes were found in responses of auditory cortical neurons to both positive and negative conditioned stimuli after training, evidence that neurons of the primary auditory cortex play a similar role in realization of the instrumental reflex and in its differential inhibition. It is suggested that the presence of groups of neurons responding by excitation or inhibition only to presentation of a stimulus with definite informative value is of great importance for differentiation.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukranian SSR, Kiev. Translated from Neirofiziologiya, Vol. 17, No. 2, pp. 212–221, March–April, 1985.     

Effect of forward masking on evoked potentials of auditory cortex in guinea pigs

Thresholds of the event-related potentials (ERPs) appearance were measured for one stationary and four moving auditory images presented in silence or under forward masking conditions. The difference between thresholds in silence and after noise masker was considered as masking level. Under the forward masking, the amplitude of the ERP to the first click in the test series decreased in guinea pig auditory cortex. Masking level decreased with the time lag between signal and masker and didn't depend on the fused auditory image localization that corresponded to the first click in different test signals. This fact can support the hypothesis that for the long test signals the initial part can be masked more than the final one. The ERPs amplitude to next clicks in test series depended on interaction of two factors: forward masking in the "masker-signal" system and interaction of separate ERPs in the series evoked by the test signal.     

Arctiid moths and bat echolocation: broad-band clicks interfere with neural responses to auditory stimuli in the nuclei of the lateral lemniscus of the big brown bat

Clicks emitted by arctiid moths interfere with the ranging ability of echolocating bats. To identify possible neural correlates of this interference, we recorded responses of single units in the nuclei of the lateral lemniscus to combinations of a broad-band click and a test signal (pure tones or frequency-modulated sweeps). In 77% of 87 units tested, clicks interfered with neural responses to the test stimuli. The interference fell into two categories: latency ambiguity and suppression. Units showing latency ambiguity responded to both the click and the test signal. However, when the click occurred within a window of approximately 3 ms before the onset of the test signal, the latency of the response to the test signal was affected. Units that were suppressed did not respond to clicks. Nevertheless, when a click was presented immediately before or simultaneously with a test signal, the response to the test signal was eliminated. Both types of units were found throughout the lateral lemniscus except for the columnar division of the ventral nucleus, where all units tested exhibited latency ambiguity. There is a close match between the single unit data and previous studies of range difference discrimination in the presence of clicks. Accepted: 10 March 1997     

Hearing sensation levels of emitted biosonar clicks in an echolocating Atlantic bottlenose dolphin

Emitted biosonar clicks and auditory evoked potential (AEP) responses triggered by the clicks were synchronously recorded during echolocation in an Atlantic bottlenose dolphin (Tursiops truncatus) trained to wear suction-cup EEG electrodes and to detect targets by echolocation. Three targets with target strengths of -34, -28, and -22 dB were used at distances of 2 to 6.5 m for each target. The AEP responses were sorted according to the corresponding emitted click source levels in 5-dB bins and averaged within each bin to extract biosonar click-related AEPs from noise. The AEP amplitudes were measured peak-to-peak and plotted as a function of click source levels for each target type, distance, and target-present or target-absent condition. Hearing sensation levels of the biosonar clicks were evaluated by comparing the functions of the biosonar click-related AEP amplitude-versus-click source level to a function of external (in free field) click-related AEP amplitude-versus-click sound pressure level. The results indicated that the dolphin's hearing sensation levels to her own biosonar clicks were equal to that of external clicks with sound pressure levels 16 to 36 dB lower than the biosonar click source levels, varying with target type, distance, and condition. These data may be assumed to indicate that the bottlenose dolphin possesses effective protection mechanisms to isolate the self-produced intense biosonar beam from the animal's ears during echolocation.     

Call recognition and female choice in a treefrog with a multicomponent call

Acoustic mating signals are typically species‐specific, and often additionally are subject to directional female preferences. Male executioner treefrogs, Dendropsophus carnifex, produce a multicomponent advertisement call composed of an introductory screech note followed by two or more click notes. Here, we tested (i) call recognition by comparing female directed phonotaxis towards individual and combined call components: screech vs. clicks vs. screech + clicks, (ii) female preferences for greater numbers of click notes and (iii) female preferences for faster call rates. The results demonstrated that screeches and clicks, presented either separately or together as a complete call, evoke similar female responses, suggesting that either note was sufficient to elicit a mate‐recognition response. Additionally, females preferred calls with greater numbers of click notes and with faster call rates. We interpret these results within the context of female mate selection in natural choruses.     

An acoustic valve within the nose of sperm whales Physeter macrocephalus

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白噪声对听觉脑干电反应(ABR)和耳蜗电图(ECochG)的影响

本文通过20例听力正常人和10例听力正常豚鼠研究了白噪声对耳蜗电图(ECochG)和听觉脑干电反应(ABR)的干涉作用。实验结果表明,白噪声比短声(信号)的声强级低30dB(SL)以上时,ECochG和ABR的振幅仅轻微减小。白噪声与短声的声强级相等时,ECochG与ABR的振幅和出现率会明显受到干涉而减小,甚至完全消失。但是,此时的耳蜗微音器电位(CM)并未观察到有明显的变化。这意味着白噪声对ECochG和ABR的干涉作用主要与围绕毛细胞基底部的突触产生的抑制密切相关。由于白噪声对ABR各波的干涉有些差异,所以认为这种抑制,可能既包括脑中抑制也包括侧方抑制。     

Responses of motor cortex neurons of the cat to auditory stimulation and their role in the instrumental food reflex

The responses of motor cortex neurons in the cat to the presentation of a single auditory click and a series of 10 clicks presented with 1,000/sec frequency were studied under conditions of chronic experiments before and after the development of an instrumental food reflex. After reflex development a single presentation of a positive conditioned stimulus (single click) markedly influenced for 7 sec the appearance of instrumental movements. At the same time, the immediate responses of motor cortex neurons to presentation of the conditioned auditory stimulus had no impact on the appearance in the motor cortex of discharges leading to the realization of instrumental movements. Consequently, motor cortex neurons do not require activation from afferent sensory inputs for the generation of such discharges. The immediate neuronal responses to conditioned stimulation did not inhibit the realization of the instrumental reflex. It is proposed that they are associated with the realization of motor function in the unconditioned defensive response evoked by the presentation of an auditory stimulus. The presence or absence of responses to auditory conditioned stimulation was dependent upon the signal meaning of the stimulus, its physical parameters, and the degree of excitability of the animal.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 17, No. 4, pp. 539–550, July–August, 1985.