title: Visualizing functional pathways in the human brain using correlation tensors and magnetic resonance imaging.
abstract: Functional magnetic resonance imaging usually detects changes in blood oxygenation level dependent (BOLD) signals from T2*-sensitive acquisitions, and is most effective in detecting activity in brain cortex which is irrigated by rich vasculature to meet high metabolic demands. We recently demonstrated that MRI signals from T2*-sensitive acquisitions in a resting state exhibit structure-specific temporal correlations along white matter tracts. In this report we validate our preliminary findings and introduce spatio-temporal functional correlation tensors to characterize the directional preferences of temporal correlations in MRI signals acquired at rest. The results bear a remarkable similarity to data obtained by diffusion tensor imaging but without any diffusion-encoding gradients. Just as in gray matter, temporal correlations in resting state signals may reflect intrinsic synchronizations of neural activity in white matter. Here we demonstrate that functional correlation tensors are able to visualize long range white matter tracts as well as short range sub-cortical fibers imaged at rest, and that evoked functional activities alter these structures and enhance the visualization of relevant neural circuitry. Furthermore, we explore the biophysical mechanisms underlying these phenomena by comparing pulse sequences, which suggest that white matter signal variations are consistent with hemodynamic (BOLD) changes associated with neural activity. These results suggest new ways to evaluate MRI signal changes within white matter.
authors.affiliation: Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, 37232; Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, 37232; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37232; Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN, 37232. Electronic address: zhaohua.ding@vanderbilt.edu.
authors.forename: Zhaohua
authors.initials: Z
authors.lastname: Ding
authors.affiliation: Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, 37232.
authors.forename: Ran
authors.initials: R
authors.lastname: Xu
authors.affiliation: Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37232.
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Bailey
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37232.
authors.forename: Tung-Lin
authors.initials: TL
authors.lastname: Wu
authors.affiliation: Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, 37232; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37232; Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, 37232.
authors.forename: Victoria L
authors.initials: VL
authors.lastname: Morgan
authors.affiliation: Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, 37232; Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN, 37232.
authors.forename: Laurie E
authors.initials: LE
authors.lastname: Cutting
authors.affiliation: Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, 37232; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37232; Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, 37232; Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, 37232.
authors.forename: Adam W
authors.initials: AW
authors.lastname: Anderson
authors.affiliation: Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, 37232; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37232; Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN, 37232; Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, 37232; Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN, 37232; Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, 37232; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232.
authors.forename: John C
authors.initials: JC
authors.lastname: Gore
mesh_terms: D000328:Adult; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology*; D063132:Connectome / Q000379:methods*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D049690:History, Ancient; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D013382:Subtraction Technique; D014584:User-Computer Interface; D014795:Visual Pathways / Q000033:anatomy & histology* / Q000502:physiology*
keywords: Functional connectivity; Functional correlation tensor; Functional magnetic resonance imaging; Functional pathways