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On the existence of a generalized non-specific task-dependent network.

Hugdahl K, Raichle ME, Mitra A, Specht K - Front Hum Neurosci (2015)

Bottom Line: We now suggest that this is because the brain utilizes the EMN network as a generalized response to tasks that exceeds a cognitive demand threshold and/or requires the processing of novel information.We further discuss how the EMN is related to the DMN, and how a network for extrinsic activity is related to a network for intrinsic activity.Finally, we discuss whether the EMN and DMN networks interact in a common single brain system, rather than being two separate and independent brain systems.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological and Medical Psychology, University of Bergen Bergen, Norway ; Division of Psychiatry, Haukeland University Hospital, Bergen Norway ; Department of Radiology, Haukeland University Hospital, Bergen Norway ; NORMENT Center of Excellence, University of Bergen Bergen, Norway.

ABSTRACT
In this paper we suggest the existence of a generalized task-related cortical network that is up-regulated whenever the task to be performed requires the allocation of generalized non-specific cognitive resources, independent of the specifics of the task to be performed. We have labeled this general purpose network, the extrinsic mode network (EMN) as complementary to the default mode network (DMN), such that the EMN is down-regulated during periods of task-absence, when the DMN is up-regulated, and vice versa. We conceptualize the EMN as a cortical network for extrinsic neuronal activity, similar to the DMN as being a cortical network for intrinsic neuronal activity. The EMN has essentially a fronto-temporo-parietal spatial distribution, including the inferior and middle frontal gyri, inferior parietal lobule, supplementary motor area, inferior temporal gyrus. We hypothesize that this network is always active regardless of the cognitive task being performed. We further suggest that failure of network up- and down-regulation dynamics may provide neuronal underpinnings for cognitive impairments seen in many mental disorders, such as, e.g., schizophrenia. We start by describing a common observation in functional imaging, the close overlap in fronto-parietal activations in healthy individuals to tasks that denote very different cognitive processes. We now suggest that this is because the brain utilizes the EMN network as a generalized response to tasks that exceeds a cognitive demand threshold and/or requires the processing of novel information. We further discuss how the EMN is related to the DMN, and how a network for extrinsic activity is related to a network for intrinsic activity. Finally, we discuss whether the EMN and DMN networks interact in a common single brain system, rather than being two separate and independent brain systems.

No MeSH data available.


Related in: MedlinePlus

Comparison of activation patterns between five of the tasks shown in Figure 2 in Duncan (2013). Reprinted with permission from the Publisher, and selected five tasks from the Bergen series of studies shown in Figure 1 of the current paper.
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Figure 5: Comparison of activation patterns between five of the tasks shown in Figure 2 in Duncan (2013). Reprinted with permission from the Publisher, and selected five tasks from the Bergen series of studies shown in Figure 1 of the current paper.

Mentions: As can be seen in Figure 1 there is a commonality of activations that involves the pre-central, middle and inferior frontal gyri, the intraparietal sulcus and inferior parietal lobule, the inferior posterior temporal region, occipital cortex. In addition, these different tasks typically also engage the dorsal part of the anterior and middle cingulate cortex (ACC) and the supplementary motor area (SMA) medially (not seen in Figure 1, but see Figure 5). The activations are seen in both hemispheres, but are more prominent in the left hemisphere. The initial reaction when seeing this pattern was that something must have gone wrong in the collection of data when preparing for the seminar lecture.


On the existence of a generalized non-specific task-dependent network.

Hugdahl K, Raichle ME, Mitra A, Specht K - Front Hum Neurosci (2015)

Comparison of activation patterns between five of the tasks shown in Figure 2 in Duncan (2013). Reprinted with permission from the Publisher, and selected five tasks from the Bergen series of studies shown in Figure 1 of the current paper.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526816&req=5

Figure 5: Comparison of activation patterns between five of the tasks shown in Figure 2 in Duncan (2013). Reprinted with permission from the Publisher, and selected five tasks from the Bergen series of studies shown in Figure 1 of the current paper.
Mentions: As can be seen in Figure 1 there is a commonality of activations that involves the pre-central, middle and inferior frontal gyri, the intraparietal sulcus and inferior parietal lobule, the inferior posterior temporal region, occipital cortex. In addition, these different tasks typically also engage the dorsal part of the anterior and middle cingulate cortex (ACC) and the supplementary motor area (SMA) medially (not seen in Figure 1, but see Figure 5). The activations are seen in both hemispheres, but are more prominent in the left hemisphere. The initial reaction when seeing this pattern was that something must have gone wrong in the collection of data when preparing for the seminar lecture.

Bottom Line: We now suggest that this is because the brain utilizes the EMN network as a generalized response to tasks that exceeds a cognitive demand threshold and/or requires the processing of novel information.We further discuss how the EMN is related to the DMN, and how a network for extrinsic activity is related to a network for intrinsic activity.Finally, we discuss whether the EMN and DMN networks interact in a common single brain system, rather than being two separate and independent brain systems.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological and Medical Psychology, University of Bergen Bergen, Norway ; Division of Psychiatry, Haukeland University Hospital, Bergen Norway ; Department of Radiology, Haukeland University Hospital, Bergen Norway ; NORMENT Center of Excellence, University of Bergen Bergen, Norway.

ABSTRACT
In this paper we suggest the existence of a generalized task-related cortical network that is up-regulated whenever the task to be performed requires the allocation of generalized non-specific cognitive resources, independent of the specifics of the task to be performed. We have labeled this general purpose network, the extrinsic mode network (EMN) as complementary to the default mode network (DMN), such that the EMN is down-regulated during periods of task-absence, when the DMN is up-regulated, and vice versa. We conceptualize the EMN as a cortical network for extrinsic neuronal activity, similar to the DMN as being a cortical network for intrinsic neuronal activity. The EMN has essentially a fronto-temporo-parietal spatial distribution, including the inferior and middle frontal gyri, inferior parietal lobule, supplementary motor area, inferior temporal gyrus. We hypothesize that this network is always active regardless of the cognitive task being performed. We further suggest that failure of network up- and down-regulation dynamics may provide neuronal underpinnings for cognitive impairments seen in many mental disorders, such as, e.g., schizophrenia. We start by describing a common observation in functional imaging, the close overlap in fronto-parietal activations in healthy individuals to tasks that denote very different cognitive processes. We now suggest that this is because the brain utilizes the EMN network as a generalized response to tasks that exceeds a cognitive demand threshold and/or requires the processing of novel information. We further discuss how the EMN is related to the DMN, and how a network for extrinsic activity is related to a network for intrinsic activity. Finally, we discuss whether the EMN and DMN networks interact in a common single brain system, rather than being two separate and independent brain systems.

No MeSH data available.


Related in: MedlinePlus