Neuronal adaptation to sound statistics in the inferior colliculus of behaving macaques does not reduce the effectiveness of the masking noise.
Neuronal adaptation to sound statistics in the inferior colliculus of behaving macaques does not reduce the effectiveness of the masking noise.
复制标题
行为猕猴下丘中的神经元对声音统计的适应不会降低掩蔽噪声的有效性。
DOI：
10.1152/jn.00875.2017
复制
发表时间：
2018
影响因子：
2.5
通讯作者：
Ramachandran,Ramnarayan
中科院分区：
文献类型：
--
作者：
Rocchi,Francesca;Ramachandran,Ramnarayan
摘要噪声背景中目标声的可检测性受声场景的叠加影响。以往的研究表明，在不规则的声环境中，麻醉豚鼠下丘（IC）神经元的动态范围向平均声压水平移动。然而，目前还不清楚这种神经适应过程如何影响声音作为掩蔽物的有效性，无论是在行为上还是在神经元编码方面。为了回答这个问题，我们测量了IC神经元的神经反应，而猕猴进行了去/不去音检测任务。猕猴检测到一个50毫秒的音调，这是同时门控与突发的噪声或嵌入在一个连续的噪声背景，其水平随机抽样（每50毫秒）从概率分布。分布的平均值与门控噪声突发的水平相匹配。两种掩蔽条件下，对音调的心理测量和IC神经测量阈值没有差异。然而，神经元放电率与水平的功能显着影响的时间特性的噪声掩蔽。与噪声分布相比，同时门控噪声引起更高的基线响应和更大的动态范围压缩。心理测量和神经测量功能的斜率显着较浅的方差分布，这表明神经元的敏感性可能会随着声音的变化而变化。我们的研究结果表明，IC神经元对声音的适应性反应并不影响噪声掩蔽信号的有效性，该信号对周围的噪声幅度保持不变。新&值得注意的是，听觉神经元适应声学场景中声音水平的统计。然而，目前还不清楚这种适应在多大程度上影响了刺激作为掩蔽的有效性。我们的研究代表了第一次尝试，以调查如何适应掩蔽刺激的统计可能与掩蔽的有效性，并在行为动物的中脑听觉神经元的单单位编码。
The detectability of target sounds embedded within noisy backgrounds is affected by the regularities that summarize acoustic sceneries. Previous studies suggested that the dynamic range of neurons in the inferior colliculus (IC) of anesthetized guinea pigs shifts toward the mean sound pressure level in irregular acoustic environments. Yet, it is unclear how this neuronal adaptation processes may influence the effectiveness of sounds as a masker, both behaviorally and in terms of neuronal encoding. To answer this question, we measured the neural response of IC neurons while macaque monkeys performed a Go/No-Go tone detection task. Macaques detected a 50-ms tone that was either simultaneously gated with a burst of noise or embedded within a continuous noise background, whose levels were randomly sampled (every 50 ms) from a probability distribution. The mean of the distribution matched the level of the gated burst of noise. Psychometric and IC neurometric thresholds to tones did not differ between the two masking conditions. However, the neuronal firing rate versus level function was significantly affected by the temporal characteristics of the noise masker. Simultaneously gated noise caused higher baseline responses and greater dynamic range compression compared with noise distribution. The slopes of psychometric and neurometric functions were significantly shallower for higher variance distributions, suggesting that neuronal sensitivity might change with the variability of the sound. Our results suggest that the adaptive response of IC neurons to sound regularities does not affect the effectiveness of the noise-masking signal, which remains invariant to surrounding noise amplitudes.NEW & NOTEWORTHYAuditory neurons adapt to the statistics of sound levels in the acoustic scene. However, it is still unclear to what extent such adaptation influences the effectiveness of the stimulus as a masker. Our study represents the first attempt to investigate how the adaptation to the statistics of masking stimuli may be related to the effectiveness of masking, and to the single-unit encoding of the midbrain auditory neurons in behaving animals.