Ex vivo diffusion-weighted MRI tractography of the Göttingen minipig limbic system

• Published in: Brain Structure and Function Vol. 225; no. 3; pp. 1055 - 1071
• Main Authors: Bech, Johannes, Orlowski, Dariusz, Glud, Andreas N., Dyrby, Tim B., Sørensen, Jens Christian H., Bjarkam, Carsten R.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2020; Springer Nature B.V
• Subjects: Aging; Animals; Biomedical and Life Sciences; Biomedicine; Cell Biology; Cingulum; Cognitive ability; Diffusion Magnetic Resonance Imaging; Female; Fornix; Information processing; Limbic system; Limbic System - anatomy & histology; Limbic System - diagnostic imaging; Magnetic resonance imaging; Mental disorders; Neural Pathways - anatomy & histology; Neural Pathways - diagnostic imaging; Neurology; Neurosciences; Original Article; Stria medullaris; Stria terminalis; Substantia alba; Swine; Swine, Miniature - anatomy & histology; White Matter - anatomy & histology; White Matter - diagnostic imaging; Fornix; Mammillothalamic tract; Cingulum; Sus scrofa; Stria medullaris; Stria terminalis
• ISSN: 1863-2653; 1863-2661; 0340-2061
• DOI: 10.1007/s00429-020-02058-x

The limbic system encompasses a collection of brain areas primarily involved in higher cognitive and emotional processing. Altered function in the limbic circuitry may play a major role in various psychiatric disorders. This study aims to provide a high-quality ex vivo diffusion-weighted MRI (DWI) tractographic overview of the Göttingen minipig limbic system pathways, which are currently not well described. This may facilitate future translational large animal studies. The study used previously obtained post-mortem DWI scans in 3 female Göttingen minipigs aging 11–15 months. The tractography performed on the DWI data set was made using a probabilistic algorithm, and regions of interest (ROIs) were defined in accordance with a histological atlas. The investigated pathways included the fornix, mammillothalamic tract, stria terminalis, stria medullaris, habenulo-interpeduncular tract, and cingulum. All the investigated limbic connections could be visualized with a high detail yielding a comprehensive three-dimensional overview, which was emphasized by the inclusion of video material. The minipig limbic system pathways displayed using tractography closely resembled what was previously described in both human studies and neuronal tracing studies from other mammalian species. We encountered well-known inherent methodological challenges of tractography, e.g., partial volume effects and complex white matter regions, which may have contributed to derouted false-positive streamlines and the failure to visualize some of the minor limbic pathway ramifications. This underlines the importance of preexisting anatomical knowledge. Conclusively, we have, for the first time, provided an overview and substantial insight of the Göttingen minipig limbic system.