title: Functional connectivity and activity of white matter in somatosensory pathways under tactile stimulations.
abstract: Functional MRI has proven to be effective in detecting neural activity in brain cortices on the basis of blood oxygenation level dependent (BOLD) contrast, but has relatively poor sensitivity for detecting neural activity in white matter. To demonstrate that BOLD signals in white matter are detectable and contain information on neural activity, we stimulated the somatosensory system and examined distributions of BOLD signals in related white matter pathways. The temporal correlation profiles and frequency contents of BOLD signals were compared between stimulation and resting conditions, and between relevant white matter fibers and background regions, as well as between left and right side stimulations. Quantitative analyses show that, overall, MR signals from white matter fiber bundles in the somatosensory system exhibited significantly greater temporal correlations with the primary sensory cortex and greater signal power during tactile stimulations than in a resting state, and were stronger than corresponding measurements for background white matter both during stimulations and in a resting state. The temporal correlation and signal power under stimulation were found to be twice those observed from the same bundle in a resting state, and bore clear relations with the side of stimuli. These indicate that BOLD signals in white matter fibers encode neural activity related to their functional roles connecting cortical volumes, which are detectable with appropriate methods.
authors.affiliation: Department of Computer Science, Chengdu University of Information Technology, Chengdu 610225, PR China; Vanderbilt University Institute of Imaging Science, Nashville, TN 37232, United States.
authors.forename: Xi
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Computer Science, Chengdu University of Information Technology, Chengdu 610225, PR China; Vanderbilt University Institute of Imaging Science, Nashville, TN 37232, United States.
authors.forename: Zhipeng
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, United States.
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Bailey
authors.affiliation: Department of Computer Science, Chengdu University of Information Technology, Chengdu 610225, PR China.
authors.forename: Jiliu
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, United States; Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37232, United States; Peabody College of Education and Human Development, Vanderbilt University, Nashville, TN 37232, United States.
authors.forename: Laurie E
authors.initials: LE
authors.lastname: Cutting
authors.affiliation: Vanderbilt University Institute of Imaging Science, Nashville, TN 37232, United States; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, United States; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, United States.
authors.forename: John C
authors.initials: JC
authors.lastname: Gore
authors.affiliation: Vanderbilt University Institute of Imaging Science, Nashville, TN 37232, United States; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, United States; Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37232, United States. Electronic address: zhaohua.ding@vanderbilt.edu.
authors.forename: Zhaohua
authors.initials: Z
authors.lastname: Ding
mesh_terms: D000328:Adult; D001931:Brain Mapping; D056324:Diffusion Tensor Imaging; D017352:Echo-Planar Imaging; D005260:Female; D006801:Humans; D008297:Male; D010812:Physical Stimulation; D013003:Somatosensory Cortex / Q000502:physiology*; D014110:Touch; D055698:Touch Perception / Q000502:physiology*; D066127:White Matter / Q000502:physiology*; D055815:Young Adult
keywords: Diffusion MRI; Functional MRI; Sensory stimulation; White matter