Input-Specific Gain Modulation by Local Sensory Context Shapes Cortical and Thalamic Responses to Complex Sounds.
Input-Specific Gain Modulation by Local Sensory Context Shapes Cortical and Thalamic Responses to Complex Sounds.
复制标题
DOI：
10.1016/j.neuron.2016.05.041
复制
发表时间：
2016-07-20
期刊：
影响因子：
16.2
通讯作者：
Sahani M
中科院分区：
文献类型：
--
作者：
Williamson RS;Ahrens MB;Linden JF;Sahani M
感觉神经元通常由一个或多个线性加权的感受场来描述感觉空间和时间的敏感性。我们发现，在听觉皮质和丘脑神经元中，每个感受场元素的重量取决于声音在时间和频率上落在它周围的局部邻域内的模式。考虑到这一变化，在具有频谱时间背景的有效感受野中，改善了对静止和复杂声音的大脑皮层和丘脑反应的预测。尽管不同的神经元和不同的大脑区域对语境的依赖不同，但它们有很强的共同的质量特征。在频谱丰富的时间音景中，当声音元素与其他频率的声音重合时，它们更有效地调节神经元的反应，而当它们之前有相似频率的声音时，则效率较低。在复杂声音的表征中，这种受局部语境驱动的不稳定可能是感觉处理中广泛存在的一个主题。神经元对声音成分的反应的增益因即时的声学背景而不同可以从神经元对复杂声音的反应中估计上下文增益场不同频率的重合声音提高了皮质和丘脑的增益，在类似频率的先前声音降低了皮质的增益，比丘脑Williamson等人的时间更长。(2016)展示了复杂声音中单个分量的编码如何取决于每个分量周围的紧邻声学邻居。这些发现挑战了非线性只跟随整合的模型，强调了接受场内细粒度的非线性相互作用。
Sensory neurons are customarily characterized by one or more linearly weighted receptive fields describing sensitivity in sensory space and time. We show that in auditory cortical and thalamic neurons, the weight of each receptive field element depends on the pattern of sound falling within a local neighborhood surrounding it in time and frequency. Accounting for this change in effective receptive field with spectrotemporal context improves predictions of both cortical and thalamic responses to stationary complex sounds. Although context dependence varies among neurons and across brain areas, there are strong shared qualitative characteristics. In a spectrotemporally rich soundscape, sound elements modulate neuronal responsiveness more effectively when they coincide with sounds at other frequencies, and less effectively when they are preceded by sounds at similar frequencies. This local-context-driven lability in the representation of complex sounds—a modulation of “input-specific gain” rather than “output gain”—may be a widespread motif in sensory processing. Gain of neuronal responses to sound components varies with immediate acoustic context “Contextual gain fields” can be estimated from neuronal responses to complex sounds Coincident sound at different frequencies boosts gain in cortex and thalamus Preceding sound at similar frequency reduces gain for longer in cortex than thalamus Williamson et al. (2016) show how encoding of individual components within complex sounds depends on the immediate acoustic neighborhood surrounding each component. These findings challenge the model that nonlinearity only follows integration, highlighting instead fine-grained nonlinear interactions within the receptive field.