Evidence for Two Independent Factors that Modify Brain Networks to Meet Task Goals

Gratton, Caterina; Laumann, Timothy O.; Gordon, Evan M.; Adeyemo, Babatunde; Petersen, Steven E.

doi:10.1016/j.celrep.2016.10.002

Cited by 151 publications

(190 citation statements)

References 55 publications

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“…Here, we showed preferential modulation of connections within those large-scale networks, while the limited number of modulated between-network connections exhibited greatest task specificity. This observation is consistent with the hypothesis that local processing is supported by out-ofnetwork connections during task performance (Gratton et al, 2016). The idea that the resting functional architecture provides a common baseline further supports the need for a full and independent resting state acquisition to allow capturing the baseline functional landscape across the frequency range, as using in-task-OFF-block-resting-state data will be constrained by the task mind-set and relaxation of task potentiation.…”

Section: Discussionsupporting

confidence: 80%

And the best task is …? Using Task potency to infer task specificity

Chauvin

Mennes

Arenas

et al. 2017

Preprint

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When an individual engages in a task, the associated evoked activities build upon already ongoing activity, itself shaped by an underlying functional connectivity baseline (Fox et al., 2009; Smith et al., 2009; Tavor et al., 2016). To facilitate understanding the building blocks of cognition we incorporate the idea that task-induced functional connectivity modulation with respect to its underlying resting state functional connectivity is task-specific. Here, we introduce a framework incorporating task potency, providing direct access to task-specificity through enabling direct comparison between task paradigms. In particular, to study functional connectivity modulations related to cognitive involvement in a task we define task potency as the amplitude of connectivity modulations away from the brain’s baseline functional connectivity architecture as observed during a resting state acquisition. We demonstrate the use of our framework by comparing three tasks (visuo-spatial working memory, reward processing, and stop signal task) available within a large cohort. Using task potency, we demonstrate that cognitive operations are supported by a common baseline of within-network interactions, supplemented by connections between large-scale networks in order to solve a specific task.Highlights-Task potency framework defines modulation of functional connectivity away from baseline resting state-More within-than between-network modulations are induced by task performance-Between-network modulations are task-specific-Edges modulated by multiple tasks are mostly within-network-The task potency can be used to define the most potent task

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Section: Discussionsupporting

confidence: 80%

And the best task is …? Using Task potency to infer task specificity

Chauvin

Mennes

Arenas

et al. 2017

Preprint

View full text Add to dashboard Cite

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“…Therefore, both residual and resting-state spontaneous correlations largely reflect the intrinsic organization of PFC. Although task-evoked changes in largescale spontaneous correlations are relatively small, they are statistically reliable (12,35) and influence behavior (27,36). Moreover, context-dependent information processing is also supported by dynamic changes in large-scale task-evoked correlations (37)(38)(39).…”

Section: Discussionmentioning

confidence: 99%

Distributed representation of context by intrinsic subnetworks in prefrontal cortex

Waskom

Wagner

2017

Proc. Natl. Acad. Sci. U.S.A.

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Human prefrontal cortex supports goal-directed behavior by representing abstract information about task context. The organizational basis of these context representations, and of representations underlying other higher-order processes, is unknown. Here, we use multivariate decoding and analyses of spontaneous correlations to show that context representations are distributed across subnetworks within prefrontal cortex. Examining targeted prefrontal regions, we found that pairs of voxels with similar context preferences exhibited spontaneous correlations that were approximately twice as large as those between pairs with opposite context preferences. This subnetwork organization was stable across task-engaged and resting states, suggesting that abstract context representations are constrained by an intrinsic functional architecture. These results reveal a principle of fine-scaled functional organization in association cortex.fMRI | resting-state | rule | cognitive control | functional organization T he cerebral cortex exhibits functional organization at multiple spatial scales. At a coarse scale, the cortex is parcellated into functional areas (1, 2) that coordinate as networks through longrange connections (3-5). These areas represent and compute information with functional circuitry that is organized more finely. Some fine-scaled, intrinsic principles have been described in detail, particularly for sensory cortex (6, 7). In contrast, the subregional organization of prefrontal cortex (PFC), which gives rise to higherorder processes, including attention, decision-making, and goaldirected action (8, 9), remains largely uncharacterized. Whether PFC representations are encoded within an equipotential system or constrained by an intrinsic functional architecture is currently unknown.Sensory cortex can be mapped by parametrically varying stimulus attributes and measuring changes in the neural response, but complex and dynamic response properties limit the effectiveness of this approach for mapping PFC and other association regions. An alternate strategy is to leverage spontaneous variability in neural activity. Neural responses to repeated presentations of sensory stimuli, or in the absence of stimulation and explicit task demands, exhibit variability that is attributed to ongoing spontaneous activity (10-13). Traditional analyses consider spontaneous activity to be noise, but there is increasing evidence that shared spontaneous variability is a signature of functional organization (14). Analyses of spontaneous correlations have been used to identify multiple large-scale functional networks (4,5,15) and boundaries between functional areas (2, 16-18) in human and nonhuman primate association cortex. The spontaneous correlation structure also mirrors established fine-scaled principles of functional organization in visual cortex, such as preferences for retinotopic position (19) and stimulus orientation (20). We therefore leveraged spontaneous activity to examine the finescaled functional organization of human PFC.We focus...

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“…These assumptions are based on multiple neuroimaging studies showing consistent activation of the fronto‐parietal network (FPN) during effortful task execution [Duncan, ; Dux et al, ; Klein et al, ; Landmann et al, ]. However, regional brain activation during tasks does not provide exact information whether activated areas actually integrate distinct brain modules [Gratton et al, ]. In terms of the network science, entire network integration can be potentially achieved through connector hubs—highly central nodes that are connected to multiple modules [Guimera and Amaral, ].…”

Section: Introductionmentioning

confidence: 99%

Transition of the functional brain network related to increasing cognitive demands

Finc

Bonna

Lewandowska

et al. 2017

Human Brain Mapping

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(1) to examine changes in the whole-brain functional network under increased cognitive demands of working memory during an n-back task, and their relationship with behavioral outcomes; and (2) to provide a comprehensive description of local changes that may be involved in the formation of the global workspace, using hub detection and network-based statistic. Our results show that network modularity decreased with increasing cognitive demands, and this change allowed us to predict behavioral performance. The number of connector hubs increased, whereas the number of provincial hubs decreased when the task became more demanding. We also found that the default mode network (DMN) increased its connectivity to other networks while decreasing connectivity between its own regions. These results, apart from replicating previous findings, provide a valuable insight into the mechanisms of the formation of the global workspace, highlighting the role of the DMN in the processes of network integration. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc.

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Evidence for Two Independent Factors that Modify Brain Networks to Meet Task Goals

Cited by 151 publications

References 55 publications

And the best task is …? Using Task potency to infer task specificity

And the best task is …? Using Task potency to infer task specificity

Distributed representation of context by intrinsic subnetworks in prefrontal cortex

Transition of the functional brain network related to increasing cognitive demands

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