LE STUDIUM / Marie Skłodowska-Curie Research Fellowship
In residence at
Pr Christophe Destrieux
Characterization of Limbic System Connectivity through fiber dissection and diffusion imaging techniques
BACKGROUND AND AIM
Although cortical elements of the limbic system are quite well defined, the underlying white matter pathways are not well detailed. This research project aims to better describe white matter tracts of the limbic system using both fiber dissection, and in and ex vivo Diffusion Weighted Imaging (DWI) techniques at various spatial resolutions. This multiple approach will: (1) improve the current anatomical knowledge on limbic connectivity; (2) validate in and ex vivo tractography by comparison to fiber dissection considered as a ground truth; (3) describe functional roles of limbic white mater tracts by studying correlations between neuropsychological alterations and microstructural changes examined by DWI.
a) in vivo data (from DWI and neuropsychological evaluations) will be obtained from 60 healthy subjects aged 82 and over previously enrolled in the FIBRATLAS project funded by the French Research Agency (ANR) and run in the host laboratory. Correlations between neuropsychological and white matter alterations studied on DWI will be examined in this group and will infer the function of the limbic white matter tracts (aim #3).
b) ex vivo data obtained from 30 cadavers will be examined: three of them obtained from volunteers previously included in the FIBRATLAS project and who will die during this proposal; and other 27 obtained from the Tours Body Donation Program. The brains will be extracted, fixed in formalin and used to study the anatomy of the limbic white matter tracts (aim #1) employing the following methods:
- Ex vivo DWI using two different clinical scanners equipped with coils, sequences and gradients adapted for imaging at magnetic fields of 3T and 7T.
- Ex vivo DWI in a preclinical scanner (11.7T) equipped with gradients allowing a very high diffusion weighting.
- Dissection according to a variant of the Klingler’s method developed by the host laboratory, to reconstruct fiber tracts into the MRI reference space. Comparison of in and ex vivo DWI data obtained for the same subjects will compose a validation study of tractography (aim #2).