PDF(Pubmed)
Abstract：
In the human brain, a multiple-demand (MD) network plays a key role in cognitive control, with core components in lateral frontal, dorsomedial frontal and lateral parietal cortex, and multivariate activity patterns that discriminate the contents of many cognitive activities. In prefrontal cortex of the behaving monkey, different cognitive operations are associated with very different patterns of neural activity, while details of a particular stimulus are encoded as small variations on these basic patterns (Sigala et al, 2008). Here, using the advanced fMRI methods of the Human Connectome Project and their 360-region cortical parcellation, we searched for a similar result in MD activation patterns. In each parcel, we compared multivertex patterns for every combination of three tasks (working memory, task-switching, and stop-signal) and two stimulus classes (faces and buildings). Though both task and stimulus category were discriminated in every cortical parcel, the strength of discrimination varied strongly across parcels. The different cognitive operations of the three tasks were strongly discriminated in MD regions. Stimulus categories, in contrast, were most strongly discriminated in a large region of primary and higher visual cortex, and intriguingly, in both parietal and frontal lobe regions adjacent to core MD regions. In the monkey, frontal neurons show a strong pattern of nonlinear mixed selectivity, with activity reflecting specific conjunctions of task events. In our data, however, there was limited evidence for mixed selectivity; throughout the brain, discriminations of task and stimulus combined largely linearly, with a small nonlinear component. In MD regions, human fMRI data recapitulate some but not all aspects of electrophysiological data from nonhuman primates.
摘要：
在人脑中,多需求（MD）网络在认知控制中起着关键作用，在侧额叶的核心部件，背侧额叶和外侧顶叶皮质，以及区分许多认知活动内容的多元活动模式。在行为猴子的前额叶皮层，不同的认知操作与非常不同的神经活动模式相关，虽然特定刺激的细节被编码为这些基本模式的小变化(Sigala等人，2008).这里,使用人类连接体项目的先进功能磁共振成像方法及其360区域皮质分裂，我们在MD激活模式中搜索了类似的结果.在每个包裹中，我们比较了三个任务的每个组合的多顶点模式(工作记忆，任务切换,和停止信号)和两个刺激类(面孔和建筑物)。尽管任务和刺激类别在每个皮层中都有区别，不同包裹的歧视强度差异很大。在MD区域强烈区分了三个任务的不同认知操作。刺激类别，相比之下,在初级和高级视觉皮层的大区域中被强烈区分，有趣的是，在与核心MD区域相邻的顶叶和额叶区域。在猴子身上，额叶神经元表现出强烈的非线性混合选择性模式，活动反映任务事件的特定连词。在我们的数据中,然而,混合选择性的证据有限；在整个大脑中，任务和刺激的判别在很大程度上线性结合，具有小的非线性分量。在MD地区，人类功能磁共振成像数据概括了非人类灵长类动物电生理数据的一些方面，但不是所有方面。
