Rapid synaptic depression explains nonlinear modulation of spectro-temporal tuning in primary auditory cortex by natural stimuli.
Rapid synaptic depression explains nonlinear modulation of spectro-temporal tuning in primary auditory cortex by natural stimuli.
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DOI：
10.1523/jneurosci.5249-08.2009
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发表时间：
2009-03-18
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影响因子：
--
通讯作者：
Shamma SA
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文献类型：
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作者：
David SV;Mesgarani N;Fritz JB;Shamma SA
在这项研究中，我们探索了更准确地解释初级听觉皮层（A1）神经元对自然声音反应的方法。听觉皮层已经进化到从复杂的自然声音中提取与行为相关的信息，但我们对其功能的大部分理解都来自使用简单合成刺激的实验。以往的神经生理学研究发现，现有的模型，如线性频谱-时间响应函数（STRF），无法捕捉自然刺激和神经反应之间的整个函数关系。为了研究这个问题，我们比较了使用自然刺激，连续语音估计的A1神经元的STRFs，使用合成涟漪噪声估计的STRFs。对于约三分之一的神经元，我们发现显着差异的STRF，通常在抑制和/或整体增益的时间动态。这种调谐的变化主要是由于语音和噪声刺激的粗略时间结构的差异。使用模拟，我们发现，刺激依赖的频谱时间调谐可以解释的模型，其中突触输入A1神经元容易受到快速非线性抑郁症。这种动态重塑的频谱时间调谐表明，突触抑制可能使自然听觉刺激的有效编码。
In this study, we explored ways to account more accurately for responses of neurons in primary auditory cortex (A1) to natural sounds. The auditory cortex has evolved to extract behaviorally relevant information from complex natural sounds, but most of our understanding of its function is derived from experiments using simple synthetic stimuli. Previous neurophysiological studies have found that existing models, such as the linear spectro-temporal response function (STRF), fail to capture the entire functional relationship between natural stimuli and neural responses. To study this problem, we compared STRFs for A1 neurons estimated using a natural stimulus, continuous speech, to STRFs estimated using synthetic ripple noise. For about one third of the neurons, we found significant differences between STRFs, usually in the temporal dynamics of inhibition and/or overall gain. This shift in tuning resulted largely from differences in the coarse temporal structure of the speech and noise stimuli. Using simulations, we found that the stimulus dependence of spectro-temporal tuning can be explained by a model in which synaptic inputs to A1 neurons are susceptible to rapid nonlinear depression. This dynamic reshaping of spectro-temporal tuning suggests that synaptic depression may enable efficient encoding of natural auditory stimuli.