Control-related systems in the human brain

Abstract

A fundamental question in cognitive neuroscience is how the human brain self-organizes to perform tasks. Multiple accounts of this self-organization are currently influential and in this article we survey one of these accounts. We begin by introducing a psychological model of task control and several neuroimaging signals it predicts. We then discuss where such signals are found across tasks with emphasis on brain regions where multiple control signals are present. We then present results derived from spontaneous task-free functional connectivity between control-related regions that dovetail with distinctions made by control signals present in these regions, leading to a proposal that there are at least two task control systems in the brain. This prompts consideration of whether and how such control systems distinguish themselves from other brain regions in a whole-brain context. We present evidence from whole-brain networks that such distinctions do occur and that control systems comprise some of the basic system-level organizational elements of the human brain. We close with observations from the whole-brain networks that may suggest parsimony between multiple accounts of cognitive control.

Figure 1. Characteristics of control regions

(a) A theoretical timecourse from a region that displays start-cue (green), sustained (gray), and error-related (red) activity. These three signals are characteristic of control regions. (b) The locations of each of the control signals across 10 task fMRI studies plotted as fixed-effect z-scores. Black squares indicate the anterior insula and anterior cingulate, the original ‘core’ of the task control system. Modified from [8•]. (c) Resting state correlations between select control regions (r > 0.175). At left in yellow, the fronto-parietal system. At right in purple, the cingulo-opercular system (‘core’ regions have white stars). Modified from [16]. (d) The regions in (c) on a PALS inflated brain surface.

Figure 2. Control systems in the context of whole-brain networks

(a) A representative picture of the areal network is shown at left, where colors denote algorithmically determined subnetworks of the network (modified from [18•]). The middle and right pictures show consensus assignments of the areal and modified voxelwise networks. Nodes of the same color correlate highly and belong to the same subnetwork. (b) The control regions from Figure 1D are plotted over the modified voxelwise subnetworks to show the correspondence between subnetworks and control systems. (c) Five putative attention-related or control-related subnetworks are shown: the fronto-parietal control system, the cingulo-opercular control system, the salience system, the dorsal attention system, and the ventral attention system. Starred subnetwork names indicate tasks or signals that activate the subnetwork in task fMRI meta-analyses.