Neural mechanisms of tone-on-tone masking: patterns of discharge rate and discharge synchrony related to rates of spontaneous discharge in the chinchilla auditory nerve.
Neural mechanisms of tone-on-tone masking: patterns of discharge rate and discharge synchrony related to rates of spontaneous discharge in the chinchilla auditory nerve.
复制标题
音调掩蔽的神经机制：与龙猫听觉神经自发放电率相关的放电率和放电同步模式。
DOI：
10.1152/jn.1986.56.6.1763
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发表时间：
1986
影响因子：
2.5
通讯作者：
Havey,DC
中科院分区：
文献类型：
--
作者：
Sinex,DG;Havey,DC
研究了在固定音调掩蔽物存在的情况下，栗鼠听觉神经纤维对短暂探测音调的反应。刺激条件与许多心理物理实验中使用的条件类似。研究了先前描述的听觉神经纤维的反应特性与心理物理声对声掩蔽特征之间的关系。在心理物理学的研究中，固定的窄带掩码产生的掩码阈值的特征模式，在高掩码水平时变得宽而不对称。在本实验1中，在30db、50db和70db声压下分别使用了5000 hz的掩模。根据对探测音调的平均反应速率估计单个听觉神经纤维的掩盖阈值。当掩蔽阈值增加到70 dB SPL时，最低的掩蔽阈值形成了与心理物理掩蔽模式相似的模式，变得更宽，更不对称。中低自发放电率纤维的屏蔽阈值与高自发放电率纤维的屏蔽阈值相同或更低。在某些频率区域，基于耳蜗失真产品响应的掩盖阈值低于任何响应探针音调的纤维的掩盖阈值；这一结果也与之前的心理物理学观察结果相似。实验2研究了在1000 Hz和50 dB声压级掩蔽物存在下，栗鼠听觉神经纤维对探测音调的反应。在这种掩蔽物的存在下，在龙猫的心理物理上测量了探针音调阈值。因此，行为和神经掩盖阈值之间的关系，在同一物种可以检查。从平均放电率响应和放电同步中估计屏蔽阈值。在观察到平均放电率变化的探针音调水平与栗鼠的行为掩盖阈值之间观察到良好的定量一致性。对于匹配特征频率的光纤，高sr光纤基于平均放电率的屏蔽阈值比中sr光纤的阈值有升高的趋势。放电率与探针音调同步的变化发生在低于栗鼠行为掩盖阈值的水平。如果放电同步可以用于检测，则代码似乎是基于与探测音调和屏蔽音调的相对同步。从具有所有sr的纤维中获得低同步屏蔽阈值。（摘要删节为400字）
Responses of chinchilla auditory nerve fibers to brief probe tones in the presence of a fixed tonal masker were obtained. The stimulus conditions were analogous to those that have been used in many psychophysical experiments. The relation between previously described response properties of auditory nerve fibers and features of psychophysical tone-on-tone masking was examined. In psychophysical studies, a fixed narrowband masker produces a characteristic pattern of masked thresholds, which becomes broad and asymmetrical at high masker levels. In the present experiment 1, a 5,000-Hz masker was presented at 30, 50, and 70 dB SPL. Masked thresholds based on the average rate of response to probe tones were estimated for single auditory nerve fibers. The lowest of these masked thresholds formed a pattern similar to the psychophysical masking pattern, becoming broader and more asymmetrical as the masker was increased to 70 dB SPL. The masked thresholds of fibers with low and medium rates of spontaneous discharge (SR) were as low as or lower than the masked thresholds of fibers with high SRs. In certain frequency regions, masked thresholds based on responses to cochlear distortion products were lower than the masked thresholds of any fiber responding to the probe tone; this result is also similar to previous psychophysical observations. In experiment 2, responses of chinchilla auditory nerve fibers to probe tones in the presence of a masker at 1,000 Hz and 50 dB SPL were studied. Probe tone thresholds in the presence of this masker have been measured psychophysically in chinchillas. Thus the relation between behavioral and neural masked thresholds in the same species could be examined. Masked thresholds were estimated from average discharge rate responses and also from discharge synchrony. Good quantitative agreement was observed between the probe tone levels at which changes in average discharge rate were observed and the chinchilla's behavioral masked thresholds. For fibers matched for characteristic frequency, the masked thresholds based on average discharge rate of high-SR fibers tended to be elevated compared with the thresholds of medium-SR fibers. Changes in discharge rate synchronized to the probe tone occurred at levels lower than the chinchilla's behavioral masked thresholds. If discharge synchrony can be used for detection, the code would appear to be based on the relative synchrony to the probe tone and to the masking tone. Low synchrony masked thresholds were obtained from fibers with all SRs.(ABSTRACT TRUNCATED AT 400 WORDS)