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Laura Harsan (Medical Physics, Advanced Molecular Imaging Research Group, Department of Radiology, University Hospital Freiburg)

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"Mapping the living mouse brain neural architecture with diffusion MRI: applications in animal models of brain disorders" / Tuesday, October 30, 2012, 17:15 h

What
  • Bernstein Seminar
When Oct 30, 2012
from 05:15 PM to 06:45 PM
Where Lecture Hall, Hansastr. 9a
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The Bernstein Center Freiburg



Bernstein Seminar
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Laura Harsan
Medical Physics
Advanced Molecular Imaging Research Group
Department of Radiology
University Hospital Freiburg
 
Mapping the living mouse brain neural architecture with diffusion MRI: applications in animal models of brain disorders

Tuesday, October 30, 2012

17:15 h

Lecture Hall (ground floor)
Bernstein Center Freiburg
Hansastraße 9A
79104 Freiburg
Abstract:
A major challenge in neuroscience is to accurately decipher and reconstruct in-vivo the entire brain circuitry at microscopic level. Histological tracing methods applied in animal models represented until recently the gold standard for investigating the structural brain connectivity pattern.
One of the most exciting developments in neuroimaging, which possibly stands as a non-invasive alternative to the histological tracing methods and extends its applicability to longitudinal human and animal studies, is Diffusion Tensor Magnetic Resonance Imaging (DT-MRI) and fiber tractography (FT)1,2. Probing the tissue microstructure by means of spatial encoding of water molecules movements, DT-MRI and FT provide a non-invasive window into the brain connectivity that was not available previously3. These approaches demonstrate their importance for gaining insight into the organization of neural networks associated with pathological conditions, or for identifying developmental/genetic cues responsible for the formation of altered brain connectivity profiles.
This presentation will summarize our experience in imaging at a microscopic scale the living mouse brain structural connectivity5 using DT-MRI and FT, in different animal models of brain pathology. We explore as well the biological basis of the obtained connectivity profiles, by comparative assessment using histological tract tracing and myelin staining. Exquisite brain anatomical details are revealed by combining MRI technologies for data acquisition (high field scanners – 9.4T and 7T – and Cryoprobe technology for the acquisition) and new post-processing algorithms. In mouse models of brain disorders we demonstrate remodeling and altering of brain neural circuits trough active plasticity mechanisms. We further discuss the potential of DT-MRI as a tool for performing a high-throughput screen of mouse models designed to explore the pathophysiological causes of major human brain diseases.
 
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In-vivo whole mouse brain fiber tracking. DT-MRI data was acquired at 7T, using an adapted mouse brain CryoProbe. Fiber-tracking was performed using a global optimization algorithm developed in our group by Reisert et al.4. Remarkable details of mouse brain fiber architecture are noticed. Abbreviations: bsc – brachium superior colliculus; cc – corpus callosum; cb – cerebellum; cg – cingulum; cp – cerebral peduncle; cx - cortex ; ec - external capsule ; fi – fimbria; hc – hippocampal commissure; hp – hippocampus; ic – internal capsule; ml – medial lemniscus; opt – optic tract.
 
  1. Johansen-Berg, H. & Rushworth, M.F. Using diffusion imaging to study human connectional anatomy. Ann. Rev. of Neurosc. 32, 75-94 (2009).
  2. Le Bihan, D. Looking into the functional architecture of the brain with diffusion MRI. Nature reviews 4, 469-480 (2003).
  3. Jones, D.K. Studying connections in the living human brain with diffusion MRI. Cortex; 44, 936-952 (2008).
  4. Reisert, M., et al. Global fiber reconstruction becomes practical. Neuroimage 54, 955-962 (2010).
  5. Harsan, L.A., et al. In vivo diffusion tensor magnetic resonance imaging and fiber tracking of the mouse brain. NMR Biomed 23, 884-896.
     
The talk is open to the public. Guests are cordially invited!
www.bcf.uni-freiburg.de

 

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