Following neuronal signals of multiple visual stimuli through cortical pathways to identify attentional gating mechanisms

通过皮质通路跟踪多种视觉刺激的神经元信号，以识别注意力门控机制

• 批准号: 331514942
• 负责人: Professor Dr. Andreas K. Kreiter
• 金额: --
• 依托单位: Abteilung Theoretische Neurobiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/331514942?language=en
• 关键词: Following; neuronal; signals; multiple; visual

Processing of natural scenes requires the visual system of our brain to handle a large number of independent visual stimuli at the same time. Often they are located close together in the retinal image. As a consequence of strong divergence and convergence of neuronal connections along the visual processing pathways, neurons typically receive signals originating from more than one visual stimulus. Nevertheless, neurons are capable to process selectively one of those stimuli if selective attention is directed to this stimulus. They are capable to respond as if only the attended stimulus would be present and suppress the often more numerous and stronger signals from other stimuli. While such attention-dependent selective stimulus processing is well documented, the underlying neuronal mechanisms are not well understood and discussed controversially.Previous results from our lab and others suggest, that this remarkable capability can be explained by attention-dependent gating mechanisms. They allow the appropriate subset of a neuron's input signals that encode the attended stimulus to pass. In contrast, all other input signals are suppressed. This gating can be explained by two major types of mechanisms. The so called asynchronous mechanisms assume, that specific circuitry interferes in an attention-dependent manner with signal delivery, e.g. by modulating synaptic transmission or canceling excitatory signals with matched inhibitory input. On the other hand, synchronous mechanisms imply specific spatio-temporal activity patterns modulating the transmission of signals, between the signal receiving neurons and the afferent input. The behaviorally relevant inputs oscillate synchronously with the signal receiving neurons in the gamma-band (30 - 100 Hz) and with a specific phase difference, allowing for optimal signal transmission. The activity patterns of all other inputs avoid this specific phase relation and are therefore rather suppressed. We have previously demonstrated corresponding patterns of attention dependent synchronization, but it is not known whether they are responsible for signal gating or rather epiphenomenal.Major goal of the project is to investigate, whether attention-dependent gating results from an asynchronous or a synchronous mechanism. Using a method we developed previously, we will tag the neuronal signals of individual stimuli. This will allow to follow the flow of information between visual cortical areas and to observe whether occasional deviations from the optimal phase are associated with reduction of transmission of signals from the attended stimulus. The results will strongly support the synchronous gating mechanism if signal transmission depends indeed strictly on phase relations. If fluctuations of signal transmission turn out to be phase-independent, the hypothesis of a synchronous mechanism has to be rejected in favor of an asynchronous mechanism.

处理自然场景需要我们大脑的视觉系统同时处理大量独立的视觉刺激。它们通常在视网膜图像中靠近在一起。由于神经元连接沿着视觉处理通路的强烈发散和会聚，神经元通常接收源自多于一个视觉刺激的信号。然而，如果选择性注意指向这些刺激，神经元能够选择性地处理这些刺激之一。它们能够做出反应，就好像只有被关注的刺激会出现一样，并抑制来自其他刺激的更多和更强的信号。虽然这种注意力依赖性选择性刺激处理已经有了很好的记录，但其潜在的神经元机制尚未得到很好的理解，并且讨论也存在争议。我们实验室和其他实验室之前的结果表明，这种显着的能力可以通过注意力依赖性门控机制来解释。它们允许神经元输入信号的适当子集通过，这些信号对所关注的刺激进行编码。相反，所有其他输入信号都被抑制。这种门控可以通过两种主要类型的机制来解释。所谓的异步机制假设特定电路以注意力依赖的方式干扰信号传递，例如通过调制突触传递或用匹配的抑制性输入消除兴奋性信号。另一方面，同步机制意味着特定的时空活动模式调制信号的传输，信号接收神经元和传入输入之间。行为相关的输入与信号接收神经元在伽马波段（30 - 100 Hz）中同步振荡，并具有特定的相位差，从而实现最佳信号传输。所有其他输入的活动模式都避免了这种特定的相位关系，因此受到抑制。我们以前已经证明了相应的模式的注意依赖同步，但它是不知道他们是否负责信号门控或更确切地epiphenomenal.Major目标的项目是调查，是否注意依赖门控结果从异步或同步机制。使用我们以前开发的方法，我们将标记单个刺激的神经元信号。这将允许跟随视觉皮层区域之间的信息流，并观察偶尔偏离最佳相位是否与来自所关注刺激的信号传输的减少相关联。结果将有力地支持同步门控机制，如果信号传输确实严格依赖于相位关系。如果信号传输的波动被证明是与相位无关的，则必须拒绝同步机制的假设，而支持异步机制。