Attention stabilizes the shared gain of V4 populations.
Attention stabilizes the shared gain of V4 populations.
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DOI：
10.7554/elife.08998
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发表时间：
2015-11-02
期刊：
影响因子：
7.7
通讯作者：
Simoncelli EP
中科院分区：
文献类型：
--
作者：
Rabinowitz NC;Goris RL;Cohen M;Simoncelli EP
感觉神经元的反应代表刺激信息，但也受到内部状态的影响。例如，当猴子将注意力集中在视觉刺激上时，视觉皮层中特定神经元子集的反应增益就会发生变化。在这里，我们开发了一个功能模型的人口活动，调查这种影响的结构。我们适合的模型，以尖峰活动的双边神经种群在V4区，记录，而动物进行刺激歧视任务下的空间注意。该模型揭示了四个独立的随时间变化的共享调制信号，其中占主导地位的两个每个目标任务相关的神经元在一个半球。在注意导向条件下，相关的共享调制信号的方差减小。这一发现为以前的观察提供了一个可解释的和简洁的解释，即注意力降低了感觉神经元的变异性和噪声相关性。最后，恢复的调制信号反映了以前的奖励，并预测随后的选择行为。DOI：http://dx.doi.org/10.7554/eLife.08998.001我们的大脑从我们的感官接收大量信息。然而，我们不能一下子处理所有这些信息;大脑必须有选择地关注这些信息的一部分。这种选择性聚焦的过程通常被称为“注意力”。在视觉系统中，这被认为是一种放大器，选择性地增强特定神经细胞子集（也称为“神经元”）的信号。Rabinowitz等人建立了一个模型来研究视觉皮层V4区域中大量神经元的活动。这个模型使得检测控制这些神经元注意力提升的隐藏信号成为可能。Rabinowitz等人的研究表明，当猴子执行视觉任务时，V4中的神经元会受到少量共享放大信号的影响，这些信号的强度会发生波动。这些放大信号选择性地影响处理视觉场景不同部分的V4神经元。此外，当猴子将注意力转移到视觉场景的一部分时，相关的放大器会减少其波动。这具有增强和稳定受影响的V4神经元的反应以及增加其独立性的副作用。Rabinowitz等人“研究结果表明，当我们把注意力集中在输入的信息上时，我们会使特定神经元的反应更大，并减少不必要的变化，以提高所表示信息的质量。下一个挑战是了解放大信号中的这些波动的原因。DOI：http://dx.doi.org/10.7554/eLife.08998.002网站
Responses of sensory neurons represent stimulus information, but are also influenced by internal state. For example, when monkeys direct their attention to a visual stimulus, the response gain of specific subsets of neurons in visual cortex changes. Here, we develop a functional model of population activity to investigate the structure of this effect. We fit the model to the spiking activity of bilateral neural populations in area V4, recorded while the animal performed a stimulus discrimination task under spatial attention. The model reveals four separate time-varying shared modulatory signals, the dominant two of which each target task-relevant neurons in one hemisphere. In attention-directed conditions, the associated shared modulatory signal decreases in variance. This finding provides an interpretable and parsimonious explanation for previous observations that attention reduces variability and noise correlations of sensory neurons. Finally, the recovered modulatory signals reflect previous reward, and are predictive of subsequent choice behavior. DOI: http://dx.doi.org/10.7554/eLife.08998.001 Our brains receive an enormous amount of information from our senses. However, we can’t deal with it all at once; the brain must selectively focus on a portion of this information. This process of selective focus is generally called “attention”. In the visual system, this is believed to operate as a kind of amplifier that selectively boosts the signals of a particular subset of nerve cells (also known as “neurons”). Rabinowitz et al. built a model to study the activity of large populations of neurons in an area of the visual cortex known as V4. This model made it possible to detect hidden signals that control the attentional boosting of these neurons. Rabinowitz et al. show that when a monkey carries out a visual task, the neurons in V4 are under the influence of a small number of shared amplification signals that fluctuate in strength. These amplification signals selectively affect V4 neurons that process different parts of the visual scene. Furthermore, when the monkey directs their attention to a part of the visual scene, the associated amplifier reduces its fluctuations. This has the side effect of both boosting and stabilizing the responses of the affected V4 neurons, as well as increasing their independence. Rabinowitz et al.’s findings suggest that when we focus our attention on incoming information, we make the responses of particular neurons larger and reduce unwanted variability to improve the quality of the represented information. The next challenge is to understand what causes these fluctuations in the amplification signals. DOI: http://dx.doi.org/10.7554/eLife.08998.002