An Emergent Population Code in Primary Auditory Cortex Supports Selective Attention to Spectral and Temporal Sound Features
An Emergent Population Code in Primary Auditory Cortex Supports Selective Attention to Spectral and Temporal Sound Features
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DOI：
10.1523/jneurosci.0693-20.2021
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发表时间：
2021-09-08
影响因子：
5.3
通讯作者：
Sutter, Mitchell L.
中科院分区：
文献类型：
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作者：
Downer, Joshua D.;Verhein, Jessica R.;Sutter, Mitchell L.
初级感觉皮层（PSC）的教科书描述围绕着单个神经元对低维感觉特征的表征，例如初级视觉皮层（V1）中的视觉对象定向，初级躯体感觉皮层（S1）中的躯体触摸位置，以及初级听觉皮层（A1）中的声音频率。通常，PSC的研究沿着沿着几个（一个或两个）刺激和/或行为维度测量神经元的反应。然而，现实世界的刺激通常是沿着许多特征维度变化的，并且行为需求不断变化。为了阐明A1在丰富的声学环境中如何支持灵活的感知，我们记录了A1神经元，而恒河猴（一男一女）执行特征选择性注意任务。我们提出的声音，不同的沿着频谱和时间特征尺寸（载波带宽和时间包络，分别）。在一个区块内，受试者参加了选择性变化检测任务的声音的一个功能。我们发现，单个神经元往往是高维的，因为它们对声音特征和任务上下文都表现出大量的混合选择性。我们发现，没有整体增强的单神经元编码的关注功能，因为注意力可以减少或增强这种编码。然而，群体水平的分析表明，神经元的集合表现出增强的编码关注的声音功能，这种人口代码跟踪受试者的表现。重要的是，具有完整的单神经元调谐但神经元之间的混洗高阶相关性的替代神经群体未能产生在完整数据中观察到的注意力相关效应。这些结果表明，在单个神经元水平上不可测量的紧急群体代码可能构成PSC中感觉表征的功能单位。
Textbook descriptions of primary sensory cortex (PSC) revolve around single neurons' representation of low-dimensional sensory features, such as visual object orientation in primary visual cortex (V1), location of somatic touch in primary somatosensory cortex (S1), and sound frequency in primary auditory cortex (A1). Typically, studies of PSC measure neurons' responses along few (one or two) stimulus and/or behavioral dimensions. However, real-world stimuli usually vary along many feature dimensions and behavioral demands change constantly. In order to illuminate how A1 supports flexible perception in rich acoustic environments, we recorded from A1 neurons while rhesus macaques (one male, one female) performed a feature-selective attention task. We presented sounds that varied along spectral and temporal feature dimensions (carrier bandwidth and temporal envelope, respectively). Within a block, subjects attended to one feature of the sound in a selective change detection task. We found that single neurons tend to be high-dimensional, in that they exhibit substantial mixed selectivity for both sound features, as well as task context. We found no overall enhancement of single-neuron coding of the attended feature, as attention could either diminish or enhance this coding. However, a population-level analysis reveals that ensembles of neurons exhibit enhanced encoding of attended sound features, and this population code tracks subjects' performance. Importantly, surrogate neural populations with intact single-neuron tuning but shuffled higher-order correlations among neurons fail to yield attention- related effects observed in the intact data. These results suggest that an emergent population code not measurable at the single-neuron level might constitute the functional unit of sensory representation in PSC.