Attentional Modulation of Receptive Field Structure

描述（由申请人提供）：提议的项目包括在清醒的猴子身上进行单单元记录研究，以测试一个简单的皮层回路模型。如果得到实证支持，该模型有望大大简化我们对空间注意的神经机制的理解。在建议的研究过程结束时，我们期望对注意力的神经机制取得重要而深刻的简化见解。我们将描述V4的关键对比度相关响应特性，这本身将是向前迈出的重要一步（Aim 1）。我们将测试V4区域的这些依赖于对比的响应特性是否与V1区域的响应特性相对应（目的1）。了解V4和v1中的对比度调制之间可能存在的任何差异非常重要。在某种程度上，它们是相似的，这将使我们能够在这两个重要的视觉处理区域之间建立机制联系，并扩大v1中处理模型的意义。我们将测试空间注意力是否调节中心-周围相互作用（目的2），这对我们对早期研究的理解有重大影响。例如，V2, V4， MT和TEO的单单元记录研究已经确定，当两个刺激同时出现在神经元的经典RF中时，反应优先由参与刺激驱动。所提出的研究将确定这种模式是否在早期阶段由于偏压抑制中心-环绕相互作用而发生。如果是这样，这将支持本提议中提出的简单模型。如果不是，这将强烈表明选择发生在第一阶段，此时rf足够大，可以包含两种刺激。最后，我们将测量对比度依赖的中心-环绕调制与注意选择之间的关系（目的3），为注意通过增加被注意刺激的有效对比度来运作的提议提供迄今为止最强有力的测试。总的来说，拟议的研究有望提供对调节注意力选择的皮层回路的更深入的理解，比迄今为止所取得的成就要深得多。

DESCRIPTION (provided by applicant): The proposed projects involve making single-unit recording studies in the awake monkey to test a simple cortical circuit model of attention. If supported empirically, the model promises to provide a major simplification in our understanding of the neural mechanisms of spatial attention. At the end of the proposed course of research, we expect to have achieved important and profoundly simplifying insights into the neural mechanisms of attention. We will have characterized key contrast-dependent response properties of V4, which itself will constitute an important step forward (Aim 1). We will have tested whether these contrast-dependent response properties in Area V4 mirror those of V1 (Aim 1). Understanding any differences that may exist between contrast modulation in V4 and V 1 is important. To the extent that they are similar, this will allow us to establish a mechanistic link between these two important visual processing areas, and to broaden the significance of models of processing in V 1. We will have tested whether spatial attention modulates center-surround interactions (Aim 2), which has major ramifications for our understanding of earlier studies. For example, single-unit recording studies in V2, V4, MT and TEO have established that when two stimuli appear together within a neuron's classical RF, the response is driven preferentially by the attended stimulus. The proposed studies will determine whether this pattern occurs as a result of biasing suppressive center-surround interactions at earlier stages. If so, this will support the simple model advanced in this proposal. If not, this would strongly suggest that the selection occurs at the first stage where RFs are large enough to encompass the two stimuli. Finally, we will have measured the relationship between contrast-dependent center-surround modulations and attentional selection (Aim 3), providing the strongest test yet of the proposal that attention operates by increasing the effective contrast of the attended stimulus. Taken together, the proposed research promises to provide a much deeper understanding of the cortical circuits that mediate attentional selection, than has been achieved to date.