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Kubicki M, Shenton ME, Maciejewski PK, Pelavin PE, Hawley KJ, Ballinger T, Swisher T, Jabbar GA, Thermenos HW, Keshavan MS, Seidman LJ, DeLisi LE. Decreased axial diffusivity within language connections: a possible biomarker of schizophrenia risk. Schizophr Res 2013; 148:67-73. [PMID: 23800617 PMCID: PMC3755869 DOI: 10.1016/j.schres.2013.06.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 05/27/2013] [Accepted: 06/03/2013] [Indexed: 10/26/2022]
Abstract
Siblings of patients diagnosed with schizophrenia are at elevated risk for developing this disorder. The nature of such risk associated with brain abnormalities, and whether such abnormalities are similar to those observed in schizophrenia, remain unclear. Deficits in language processing are frequently reported in increased risk populations. Interestingly, white matter pathology involving fronto-temporal language pathways, including arcuate fasciculus (AF), uncinate fasciculus (UF), and inferior occipitofrontal fasciculus (IOFF), are frequently reported in schizophrenia. In this study, high spatial and directional resolution diffusion MRI data was obtained on a 3T magnet from 33 subjects with increased familial risk for developing schizophrenia, and 28 control subjects. Diffusion tractography was performed to measure white matter integrity within AF, UF, and IOFF. To understand these abnormalities, Fractional Anisotropy (FA, a measure of tract integrity) and Trace (a measure of overall diffusion), were combined with more specific measures of axial diffusivity (AX, a putative measure of axonal integrity) and radial diffusivity (RD, a putative measure of myelin integrity). Results revealed a significant decrease in Trace within IOFF, and a significant decrease in AX in all tracts. FA and RD anomalies, frequently reported in schizophrenia, were not observed. Moreover, AX group effect was modulated by age, with increased risk subjects demonstrating a deviation from normal maturation trajectory. Findings suggest that familial risk for schizophrenia may be associated with abnormalities in axonal rather than myelin integrity, and possibly associated with disruptions in normal brain maturation. AX should be considered a possible biomarker of risk for developing schizophrenia.
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Affiliation(s)
- M Kubicki
- Psychiatry Neuroimaging Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
| | - ME Shenton
- Psychiatry Neuroimaging Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA,VA Boston Healthcare System, Brockton, MA, United States
| | | | - PE Pelavin
- Psychiatry Neuroimaging Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - KJ Hawley
- Psychiatry Neuroimaging Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - T Ballinger
- Psychiatry Neuroimaging Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - T Swisher
- Psychiatry Neuroimaging Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - GA Jabbar
- Harvard Medical School, Boston, MA, USA
| | - HW Thermenos
- Harvard Medical School, Boston, MA, USA,Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, USA; Massachusetts Mental Health Center Division of Public Psychiatry, Boston, MA, USA
| | - MS Keshavan
- Harvard Medical School, Boston, MA, USA,Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, USA; Massachusetts Mental Health Center Division of Public Psychiatry, Boston, MA, USA
| | - LJ Seidman
- Harvard Medical School, Boston, MA, USA,Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA,Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, USA; Massachusetts Mental Health Center Division of Public Psychiatry, Boston, MA, USA
| | - LE DeLisi
- VA Boston Healthcare System, Brockton, MA, United States,Harvard Medical School, Boston, MA, USA
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Makris N, Preti MG, Asami T, Pelavin P, Campbell B, Papadimitriou GM, Kaiser J, Baselli G, Westin CF, Shenton ME, Kubicki M. Human middle longitudinal fascicle: variations in patterns of anatomical connections. Brain Struct Funct 2013; 218:951-68. [PMID: 22782432 PMCID: PMC3500586 DOI: 10.1007/s00429-012-0441-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 06/19/2012] [Indexed: 10/28/2022]
Abstract
Based on high-resolution diffusion tensor magnetic resonance imaging (DTI) tractographic analyses in 39 healthy adult subjects, we derived patterns of connections and measures of volume and biophysical parameters, such as fractional anisotropy (FA) for the human middle longitudinal fascicle (MdLF). Compared to previous studies, we found that the cortical connections of the MdLF in humans appear to go beyond the superior temporal (STG) and angular (AG) gyri, extending to the temporal pole (TP), superior parietal lobule (SPL), supramarginal gyrus, precuneus and the occipital lobe (including the cuneus and lateral occipital areas). Importantly, the MdLF showed a striking lateralized pattern with predominant connections between the TP, STG and AG on the left and TP, STG and SPL on the right hemisphere. In light of the results of the present study, and of the known functional role of the cortical areas interconnected by the MdLF, we suggested that this fiber pathway might be related to language, high order auditory association, visuospatial and attention functions.
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Affiliation(s)
- N Makris
- Department of Psychiatry, Neurology and Radiology Services, Center for Morphometric Analysis, A Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA.
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