INTEGRATIVE APPROACH TO CORTICAL COGNITIVE NETWORKS

这个项目有两个主要目标。首先，确定工作记忆过程中联想皮层（前额叶和后顶叶）认知神经元网络的结构和功能特性。第二个目标主要是方法论上的：证实工作记忆中神经活动和血流动力学变化之间的耦合。这两个目标将在猴子身上通过四种微创和行为兼容的记录方法来实现：近红外光谱（NIRS）、表面场电位（FP）记录、局部场电位（LFP）记录和单元活动记录。用硬膜外探头同时记录近红外光谱信号和表面FPs。单位活动和局部场电位（LFPs）也将通过硬膜外微电极同时记录。基于认知网络结构的特定假设和每种方法的空间分辨率，将四种方法结合使用，以测试空间延迟反应（DR）和非空间延迟样本匹配（DMS）两种工作记忆任务执行过程中感兴趣区域的神经激活和血流动力学变化的三个特定假设。分析将集中在工作记忆中感觉刺激保留期间的神经和血流动力学活动。近红外光谱（NIRS）、FP和单位数据将与每一个与待测试的特定假设最相关的变量相关：皮层位置、刺激或记忆、任务、试验时间和正确表现水平。在认知功能的神经-血流动力学耦合研究中，将特别强调近红外光谱信号与细胞放电电表现之间的相关性。这些相关性有望为人类认知中的功能成像信号（如BOLD fMRI获得的信号）的神经元基础提供重要信息。

This project has two major objectives. The first is to identify structural and functional properties of cognitive neuronal networks in cortex of association (prefrontal and posterior parietal) during working memory. The second objective is largely methodological: to substantiate the coupling between neural activity and hemodynamic changes in working memory. Both objectives will be pursued in the monkey by the combined use of four minimally invasive and behavior-compatible recording methods: near-infrared spectroscopy (NIRS), surface field-potential (FP) recording, local field-potential (LFP) recording, and unit-activity recording. NIRS signals and surface FPs will be recorded simultaneously with epidural probes. Unit activity and local field potentials (LFPs) will also be recorded simultaneously by means of transdural microelectrodes. Based on certain assumptions of cognitive network architecture and the spatial resolution of each method, the four methods will be used in combination to test three specific hypotheses of neural activation and hemodynamic change in the regions of interest during the performance of two working-memory tasks, spatial delayed response (DR) and non-spatial delayed matching to sample (DMS). The analysis will focus on the neural and hemodynamic activity during the retention of a sensory stimulus in working memory. NIRS, FP, and unit data will be correlated with each of the variables most relevant to the specific hypotheses to be tested: cortical location, stimulus or memorandum, task, time of trial, and level of correct performance. In the study of neural-hemodynamic coupling in cognitive function, special emphasis will be placed on the correlations between NIRS signals and electrical manifestations of cell discharge. These correlations are expected to provide crucial information on the neuronal basis of functional imaging signals, such as those obtained by BOLD fMRI, in human cognition.