Brain Imaging and Behavior

, Volume 7, Issue 3, pp 316–325

Genetic contributions to changes of fiber tracts of ventral visual stream in 22q11.2 deletion syndrome

  • Zora Kikinis
  • Nikos Makris
  • Christine T. Finn
  • Sylvain Bouix
  • Diandra Lucia
  • Michael J. Coleman
  • Erica Tworog-Dube
  • Ron Kikinis
  • Raju Kucherlapati
  • Martha E. Shenton
  • Marek Kubicki
Original Research

DOI: 10.1007/s11682-013-9232-5

Cite this article as:
Kikinis, Z., Makris, N., Finn, C.T. et al. Brain Imaging and Behavior (2013) 7: 316. doi:10.1007/s11682-013-9232-5

Abstract

Patients with 22q11.2 deletion syndrome (22q11.2DS) represent a population at high risk for developing schizophrenia, as well as learning disabilities. Deficits in visuo-spatial memory are thought to underlie some of the cognitive disabilities. Neuronal substrates of visuo-spatial memory include the inferior fronto-occipital fasciculus (IFOF) and the inferior longitudinal fasciculus (ILF), two tracts that comprise the ventral visual stream. Diffusion Tensor Magnetic Resonance Imaging (DT-MRI) is an established method to evaluate white matter (WM) connections in vivo. DT-MRI scans of nine 22q11.2DS young adults and nine matched healthy subjects were acquired. Tractography of the IFOF and the ILF was performed. DT-MRI indices, including Fractional anisotropy (FA, measure of WM changes), axial diffusivity (AD, measure of axonal changes) and radial diffusivity (RD, measure of myelin changes) of each of the tracts and each group were measured and compared. The 22q11.2DS group showed statistically significant reductions of FA in IFOF in the left hemisphere. Additionally, reductions of AD were found in the IFOF and the ILF in both hemispheres. These findings might be the consequence of axonal changes, which is possibly due to fewer, thinner, or less organized fibers. No changes in RD were detected in any of the tracts delineated, which is in contrast to findings in schizophrenia patients where increases in RD are believed to be indicative of demyelination. We conclude that reduced axonal changes may be key to understanding the underlying pathology of WM leading to the visuo-spatial phenotype in 22q11.2DS.

Keywords

22q11.2 deletion syndrome (22q11.2DS,VCFS) Diffusion Tensor MRI (DT-MRI) Fractional anisotropy (FA) Axial diffusivity (AD) Inferior fronto-occipital fasciculus (IFOF) Inferior longitudinal fasciculus (ILF) High-risk schizophrenia 

Supplementary material

11682_2013_9232_Fig3_ESM.jpg (13 kb)
Figure S1

Graphical presentation of subjects’ age (JPEG 13 kb)

11682_2013_9232_MOESM1_ESM.tif (280 kb)
Hiresulotion image file (TIFF 279 kb)

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Zora Kikinis
    • 1
  • Nikos Makris
    • 1
    • 2
  • Christine T. Finn
    • 3
  • Sylvain Bouix
    • 1
  • Diandra Lucia
    • 1
  • Michael J. Coleman
    • 1
  • Erica Tworog-Dube
    • 4
  • Ron Kikinis
    • 5
  • Raju Kucherlapati
    • 6
  • Martha E. Shenton
    • 1
    • 5
    • 7
  • Marek Kubicki
    • 1
    • 7
  1. 1.Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Brigham and Women’s HospitalHarvard Medical SchoolBostonUSA
  2. 2.Psychiatry and Neurology Departments, Massachusetts General HospitalHarvard Medical SchoolBostonUSA
  3. 3.Department of PsychiatryDartmouth Hitchcock Medical CenterLebanonUSA
  4. 4.Department of Medicine, Brigham and Women’s HospitalHarvard Medical SchoolBostonUSA
  5. 5.Surgical Planning Laboratory, Department of Radiology, Brigham and Women’s HospitalHarvard Medical SchoolBostonUSA
  6. 6.Department of GeneticsHarvard Medical SchoolBostonUSA
  7. 7.Clinical Neuroscience Division, Laboratory of Neuroscience, Department of Psychiatry, VA Boston Healthcare SystemHarvard Medical SchoolBrocktonUSA

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