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Proc Natl Acad Sci U S A. 2014 Sep 30;111(39):14247-52. doi: 10.1073/pnas.1322173111. Epub 2014 Sep 15.

Network measures predict neuropsychological outcome after brain injury.

Author information

1
Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA 52242;
2
Departments of Neurology.
3
Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA 52242; Department of Psychology, University of Iowa, Iowa City, IA 52242; and.
4
Departments of Neurology, Radiology, Anatomy and Neurobiology, and Departments of Psychology and Neurosurgery, Washington University School of Medicine, St. Louis, MO 63110; Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130.
5
Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA 52242; Department of Psychology, University of Iowa, Iowa City, IA 52242; and daniel-tranel@uiowa.edu.

Abstract

Hubs are network components that hold positions of high importance for network function. Previous research has identified hubs in human brain networks derived from neuroimaging data; however, there is little consensus on the localization of such hubs. Moreover, direct evidence regarding the role of various proposed hubs in network function (e.g., cognition) is scarce. Regions of the default mode network (DMN) have been frequently identified as "cortical hubs" of brain networks. On theoretical grounds, we have argued against some of the methods used to identify these hubs and have advocated alternative approaches that identify different regions of cortex as hubs. Our framework predicts that our proposed hub locations may play influential roles in multiple aspects of cognition, and, in contrast, that hubs identified via other methods (including salient regions in the DMN) might not exert such broad influence. Here we used a neuropsychological approach to directly test these predictions by studying long-term cognitive and behavioral outcomes in 30 patients, 19 with focal lesions to six "target" hubs identified by our approaches (high system density and participation coefficient) and 11 with focal lesions to two "control" hubs (high degree centrality). In support of our predictions, we found that damage to target locations produced severe and widespread cognitive deficits, whereas damage to control locations produced more circumscribed deficits. These findings support our interpretation of how neuroimaging-derived network measures relate to cognition and augment classic neuroanatomically based predictions about cognitive and behavioral outcomes after focal brain injury.

KEYWORDS:

brain hubs; fMRI; functional connectivity; neuropsychology

PMID:
25225403
PMCID:
PMC4191760
DOI:
10.1073/pnas.1322173111
[Indexed for MEDLINE]
Free PMC Article

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