Structure Specific Analysis of white and gray matter in the rat brain

Tract specific Analysis (TSA) uses continuous medial modeling for structure- specific analysis of diffusion in sheet-like white matter tracts in the human brain. The medial geometry provides both a skeleton surface (the medial surface) and two “spoke” vectors from the skeleton to the boundary of the structure. Diffusion properties such as fractional anisotropy (FA) are sampled along the spokes and their mean is projected onto the skeleton for statistical testing on the medial surface. TSA enhances sensitivity and reduces multiple comparisons.

In a new abstract to appear at the Joint Annual Meeting ISMRM-ESMRMB 2014, we construct medial models of white matter tracts in the rat brain. We further apply the medial modeling approach to include the isocortex. Compared to human cortex, the lissencephalic rat cortex is readily modeled with a medial surface and we can resolve higher FA with DTI. We apply the new medial models to the study of the neurobiology of chronic stress in rats. Tracts connecting to the hippocampus and prefrontal cortex are of particular interest, since these areas are widely reported to be affected by stress and are important in mediating stress response. We therefore built medial models of corpus callosum, fimbria / fornix, and the internal capsule.


Medial skeletons of structure-specific analysis models in the white brain, overlaid on the RGB-FA image of a rat template.

The results will be presented as an e-poster in Milan.

  • P. A. Cook, P. A. Yushkevich, S. Tian, S. Luz, S. Bhatnagar, and J. C. Gee, “Structure Specific Analysis of white and gray matter in the rat brain after exposure to chronic stress,” in Proceedings 22nd Scientific Meeting, International Society for Magnetic Resonance in Medicine, Milan, Italy, 2014, p. 4554.
    author = {Cook, Philip A. and Yushkevich, Paul A. and Tian, Sijie and Luz,
    Sandra and Bhatnagar, Seema and Gee, James C.},
    title = {{S}tructure {S}pecific {A}nalysis of white and gray matter in the
    rat brain after exposure to chronic stress},
    booktitle = {{P}roceedings 22nd {S}cientific {M}eeting, {I}nternational {S}ociety
    for {M}agnetic {R}esonance in {M}edicine, {M}ilan, {I}taly},
    year = {2014},
    pages = {4554},
    abstract = {Language deficits are widely reported in frontotemporal dementia (FTD),
    including non-fluent primary progressive aphasia (naPPA), semantic-variant
    primary progressive aphasia (svPPA) behavioral variant FTD (bvFTD).
    We hypothesize that these deficits are due to disruption of a large-scale
    neural network involving both language and executive resources. Here
    we use multi-modal MRI and sparse statistical methods to evaluate
    whether imaging of white matter (WM) with diffusion MRI enhances
    prediction of the neuroanatomic basis for their deficit when combined
    with cortical thickness derived from T1 MRI.},
    keywords = {SLC1011},
    owner = {pcook},
    timestamp = {2014.03.13}