Delineation of a task-demand dependent rostrocaudal gradient in the salience network

突显网络的特征是背侧前扣带回和双侧脑岛的共同激活，并被分配了基本的认知过程，如发出任务背景重要的信号，或在其他大规模网络之间切换以促进注意力的获得。已经提出dACC和脑岛大致遵循嘴/尾的划分；因此，突出网络也应该遵循嘴-尾的梯度，而对这一点的描述及其功能意义，是开始理解与一系列认知任务中涉及的大量脑功能网络相关的认知功能的重要的第一步。我们在已发表的研究中观察到了这种任务-需求相关的显著网络的旋尾梯度，即当需要感觉运动加工时，协调的显著网络活动最晚，当需要外部定向注意时，协调的显著网络活动居中，当执行推理和内部言语认知操作时，协调的显著网络活动最前面。这种组织与大脑组织的进化理论是一致的，更多的正面认知处理只对应于人类的认知过程，如推理和内部言语。到目前为止，这一显著网络中依赖于任务需求的旋尾梯度理论是基于跨实验、跨样本和跨数据收集站点的观察而发展起来的。拟议的5年计划涉及使用N-Back和Sternberg工作记忆任务平台的变化，通过受试者内部对刺激呈现的方式(视觉、语言和听觉)和数据收集的方式(fMRI和EEG)的操纵来展示对这些不同配置的显著网络的控制。言语情态的表现包括一系列的字母、无意义的音节和单词，以视觉或听觉的方式呈现。非语言通道中的刺激显示包括视觉上呈现的设计、空间构型或运动，或者听觉上呈现的音调或其他非语言声音，可能还描绘了运动或空间构型。与各种显著配置共同激活的所有网络预计是依赖于形态的。每个变量及其组合对显著网络的性能和肩尾梯度的影响，是开始了解与大量功能大脑网络相关的认知功能的重要第一步。这将在建议延长5年的10个多模式实验中进行探索。这项研究对加拿大人很重要，因为需要精确了解大脑网络的功能，通过大脑训练和/或神经调节来操纵这些大脑网络，以增强认知功能。

The salience network is characterized by co-activation of the dorsal anterior cingulate and the bilateral insula, and has been assigned fundamental cognitive processes, such as signalling that a task context is important, or switching between other large-scale networks to facilitate access to attention. The dACC and insula have been proposed to follow a roughly rostral/caudal division; therefore, the salience network should also follow a rostrocaudal gradient, and delineation of this, and its functional significance, is an important first step in beginning to understanding the cognitive functions associated with the vast array of functional brain networks involved in an array of cognitive tasks. We have observed such a task-demand dependent rostrocaudal gradient in the salience network in our published studies, such that coordinated salience network activity is most posterior when sensorimotor processing is required, intermediate when externally oriented attention is required, and most anterior when reasoning and inner speech cognitive operations are executed. This organization is congruent with evolutionary theories of brain organization, with more frontal cognitive processing corresponding to exclusively human cognitive processes like reasoning and inner speech. To date this theory of task-demand dependent rostrocaudal gradient in the salience network has been developed based on observations across experiments, across samples, and across data collection sites. The proposed 5 year plan involves demonstrating control over these different configurations of the salience network using within-subjects manipulations of modality of stimulus presentation (visual, verbal and auditory) and modality of data collection (fMRI and EEG) using variations of the N-back and Sternberg working memory task platforms. Displays in the verbal modality include series of letters, nonsense syllables and words, presented visually or auditorily. Stimulus displays in the non-verbal modality include designs, spatial configurations or motions presented visually, or tones or other non-verbal sounds presented auditorily, possibly also depicting motion or spatial configurations. All networks that co-activate with the various salience configuration are anticipated to be modality dependent. The effect of each variable, and combinations, on performance and the rostrocaudal gradient of the salience network, is an important first step in beginning to understanding the cognitive functions associated with the vast array of functional brain networks. This will be explored over 10 multimodal experiments proposed to extend over 5 years. This research is important to Canadians because a precise understanding of the function of brain networks is required for manipulation of those brain networks, through brain training and/or neuromodulation, to enhance cognitive functioning.