title: From "rest" to language task: Task activation selects and prunes from broader resting-state network.
abstract: Resting-state networks (RSNs) show spatial patterns generally consistent with networks revealed during cognitive tasks. However, the exact degree of overlap between these networks has not been clearly quantified. Such an investigation shows promise for decoding altered functional connectivity (FC) related to abnormal language functioning in clinical populations such as temporal lobe epilepsy (TLE). In this context, we investigated the network configurations during a language task and during resting state using FC. Twenty-four healthy controls, 24 right and 24 left TLE patients completed a verb generation (VG) task and a resting-state fMRI scan. We compared the language network revealed by the VG task with three FC-based networks (seeding the left inferior frontal cortex (IFC)/Broca): two from the task (ON, OFF blocks) and one from the resting state. We found that, for both left TLE patients and controls, the RSN recruited regions bilaterally, whereas both VG-on and VG-off conditions produced more left-lateralized FC networks, matching more closely with the activated language network. TLE brings with it variability in both task-dependent and task-independent networks, reflective of atypical language organization. Overall, our findings suggest that our RSN captured bilateral activity, reflecting a set of prepotent language regions. We propose that this relationship can be best understood by the notion of pruning or winnowing down of the larger language-ready RSN to carry out specific task demands. Our data suggest that multiple types of network analyses may be needed to decode the association between language deficits and the underlying functional mechanisms altered by disease. Hum Brain Mapp 38:2540-2552, 2017. © 2017 Wiley Periodicals, Inc.
authors.affiliation: Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania.|Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Gaelle E
authors.identifier: 0000-0003-4120-0474
authors.initials: GE
authors.lastname: Doucet
authors.affiliation: Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Xiaosong
authors.initials: X
authors.lastname: He
authors.affiliation: Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Sperling
authors.affiliation: Department of Neurosurgery, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Ashwini
authors.initials: A
authors.lastname: Sharan
authors.affiliation: Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Joseph I
authors.initials: JI
authors.lastname: Tracy
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D004569:Electroencephalography; D004827:Epilepsy / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D049268:Positron-Emission Tomography; D012146:Rest / Q000502:physiology*; D055815:Young Adult
keywords: functional connectivity; language; resting-state network; temporal lobe epilepsy