Dual Feedback Streams and Laminar Integration of Long-range Inter-areal Processes in the Early Visual System

早期视觉系统中远程区域间过程的双反馈流和层整合

• 批准号: 431394854
• 负责人: Professor Dr. Pascal Fries
• 金额: --
• 依托单位: Stem Cell and Brain Research Institute (SBRI)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/431394854?language=en
• 关键词: Dual; Feedback; Streams; Laminar; Integration

Cortical feedback plays a critical role in perceptual-cognitive integration and in major hypotheses on brain function, including predictive coding theory. We aim to investigate the integrative roles of two feedback pathways that have been identified in the inter-areal projections of primate cerebral cortex in the framework of a multidisciplinary project that will use neuroimaging, electrophysiology and anatomy. The two feedback pathways in supra- and infragranular cortical layers show distinct topographical features: a long-distance, diffusely projecting pathway in infragranular layers and a short-distance pathway whose projections are more focal and confined to supragranular layers. Importantly, the specific functions of these two pathways are unknown. Objectives 1 and 2 probes these pathways by studying laminar dependent activity in early visual areas during cognitive tasks requiring perceptual integration and attention in human and nonhuman primates while performing tasks requiring long-range cortical interaction: figure/ground, motion coherence and spatial vs feature selective attention. Objective 1, in human, uses laminar-resolution functional imaging with fMRI at 7T to explore what stimulus conditions generate differential activation of supra and infragranular layers and causal modeling to infer directed inter-areal effective connectivity. We will explore three tasks: (1) contextual effects on surface color perception that influence (i) the visual stream of origin of feedback signals and (ii) stimulus predictability; (2) the influence of motion coherence and stimulus expectation on feedback to early visual areas; (3) the role of spatial and feature selective attention on the laminar profile of activity. We expect that these experiments will reveal conditions that differentially affect the two feedback streams, thus, informing us about their different functional roles. Objective 2, in marmoset uses multi-site depth electrodes to assess layer-specific activation patterns and directed inter-areal interactions via layer-specific optogenetic activation of the two feedback pathways to probe their causal relevance. We expect that the results will inform us about the differential roles of the two feedback pathways in cortical processing, which will allow more accurate models of cortical processing to be developed in a predictive coding framework. Objective 3 addresses the nature and frequency of long-distance inhibitory connections between cortical areas and interstitial neurons and cortex, investigating if they are preferentially associated with a particular circuit. Such inhibitory processes are predicted to have profound impact on inter-areal processing through effects on oscillation and synchrony. We predict the proposed work will contribute to understanding the canonical cortical microcircuits and the computations they support in a predictive coding framework and thereby furthering understanding the neuronal basis of psychiatric disorders.

皮质反馈在知觉认知整合和大脑功能的主要假设（包括预测编码理论）中发挥着关键作用。我们的目标是在使用神经影像学、电生理学和解剖学的多学科项目的框架内，研究在灵长类大脑皮层的区域间投射中发现的两种反馈途径的综合作用。颗粒上和颗粒下皮质层中的两条反馈通路显示出不同的地形特征：颗粒下层中的长距离、弥散投射通路和投射更集中并局限于颗粒上层的短距离通路。重要的是，这两条途径的具体功能尚不清楚。目标 1 和 2 通过研究人类和非人类灵长类动物在执行需要远程皮层交互的任务时需要知觉整合和注意力的认知任务期间早期视觉区域的层状依赖性活动来探索这些途径：图形/背景、运动连贯性以及空间与特征选择性注意力。目标 1 在人体中使用 7T 功能磁共振成像的层流分辨率功能成像来探索哪些刺激条件会产生颗粒上层和颗粒下层的差异激活，并通过因果模型推断定向区域间有效连接。我们将探讨三个任务：（1）对表面颜色感知的上下文影响，影响（i）反馈信号起源的视觉流和（ii）刺激可预测性； (2)运动连贯性和刺激预期对早期视觉区域反馈的影响； (3)空间和特征选择性注意对活动层流剖面的作用。我们期望这些实验将揭示对两个反馈流产生不同影响的条件，从而让我们了解它们的不同功能作用。目标 2，在狨猴中使用多位点深度电极来评估层特异性激活模式，并通过两个反馈通路的层特异性光遗传学激活来定向区域间相互作用，以探测它们的因果相关性。 我们期望结果将告诉我们两种反馈通路在皮质处理中的不同作用，这将允许在预测编码框架中开发更准确的皮质处理模型。 目标 3 解决皮质区域与间质神经元和皮质之间长距离抑制连接的性质和频率，研究它们是否优先与特定回路相关。预计这种抑制过程将通过对振荡和同步的影响对区域间处理产生深远的影响。我们预测拟议的工作将有助于理解规范的皮质微电路及其在预测编码框架中支持的计算，从而进一步了解精神疾病的神经元基础。