Stamatios N Sotiropoulos¹, Xu Chen², Stephen M Smith¹, David C Van Essen³, Timothy E Behrens¹, Thomas E Nichols², and Saad Jbabdi^1
1FMRIB Centre, University of Oxford, Oxford, United Kingdom, ²Department of Statistics, University of Warwick, Coventry, United Kingdom, ³Department of Anatomy & Neurobiology, Washington University, St Louis, MO, United States

There is great interest in understanding population variability of brain connectivity patterns, and the genetic contributions to this variability. Heritability, the proportion of variability attributable to genetic sources, is a quantitative measure that allows the identification of phenotypes. In this work, we examine the heritability of structural connections using diffusion MRI data from the HCP. We compute whole-brain structural connectivity matrices and infer on heritability using permutation testing. Importantly, we localise regions with most heritable connections across different cortical parcellations and compare to heritability trends of cortical morphological features.

Christopher J. Steele¹, Alfred Anwander¹, Pierre-Louis Bazin¹, Robert Trampel¹, Andreas Schaefer¹, Robert Turner¹, Narender Ramnani², and Arno Villringer^1
1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Sachsen, Germany, ²Royal Holloway University of London, Egham, Surrey, United Kingdom

The cortico-cerebellar loops form one of the largest systems in the brain, yet we have virtually no knowledge about cerebellar anatomical connectivity in humans. We acquired sub-mm cerebellar diffusion images and applied highly specific tractography to understand the cortico-cerebellar loops and provide insight on the influence of motor and non-motor dentate nucleus territories on the brain. We found the first structural evidence that the human dentate nucleus contains a motor/non-motor topographical organisation and, crucially, present novel evidence that the relative influence of non-motor functions of the cerebellum may have increased relative to that of our primate cousins.

Andrea De Rinaldis^1,2, Fulvia Palesi^2,3, Gloria Castellazzi^1,2, Fernando Calamante^4,5, Nils Muhlert^6,7, J Donald Tournier^4,5, Giovanni Magenes¹, Egidio D'Angelo^2,8, and Claudia AM Wheeler-Kingshott^6
1Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, PV, Italy, ²Brain Connectivity Center, C. Mondino National Neurological Institute, Pavia, PV, Italy, ³Department of Physics, University of Pavia, Pavia, PV, Italy, ⁴The Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Heidelberg, Victoria, Australia, ⁵Department of Medicine, Austin Health and Northern Health, University of Melbourne, Heidelberg, Victoria, Australia, ⁶NMR Research Unit, Department of Neuroinflammation, Queen Square MS Centre, UCL Institute of Neurology, London, England, United Kingdom, ⁷Department of Psychology, Cardiff University, Cardiff, Wales, United Kingdom, ⁸Department of Brain and Behavioral Sciences, University of Pavia, Pavia, PV, Italy

Cerebellar involvement in cognition is becoming increasingly evident; this is thought to occur through the cerebello-cortical loop, composed of two main pathways: an efferent cerebello-thalamo-cortical pathway and an afferent cortico-ponto-cerebellar pathway. The former has already been reconstructed in vivo using probabilistic tractography. We applied the same method to reconstruct the latter pathway and to describe it both anatomically and quantitatively. The main finding is that most of the cortico-ponto-cerebellar streamlines connect cerebral associative areas with their cerebellar cognitive counterpart. This result improves our understanding of cerebello-cortical connections and provide a plausible pathway through which the cerebellum can influence cognition.

Marco Lawrenz^1,2, Stefanie Brassen^1,2, and Jürgen Finsterbusch^1,2
1Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Hamburg, Germany, ²Neuroimage Nord, University Medical Centers Hamburg-Kiel-Lübeck, Hamburg-Kiel-Lübeck, Hamburg-Kiel-Lübeck, Germany

Double-wave-vector diffusion-weighting experiments with two weighting periods applied successively offer access to microscopic tissue. Rotationally invariant measures of the microscopic diffusion anisotropy such as the MA index may yield additional information complementary to DTI. Recent studies showed that MA can be determined in the living human brain, and normal values and their variation in a group of young healthy volunteers have been reported. In this study, DWV and DTI measurements were performed in a group of old, healthy volunteers in order to detect age-related changes of the FA and MA.

Shir Hofstetter¹ and Yaniv Assaf^1,2
1Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel, Israel, ²Neurobiology, Tel Aviv University, Israel, Israel

This study investigates the initial temporal and spatial progression of neuroplasticity using the Morris water maze training. We looked at the evolution of plasticity at different stages of the learning process as well as the effect of the overall time of the task on these changes. Results provide a first demonstration of an order to the progression of neuroplasticity. Few minutes of training can cause changes in the tissue, and the extent of this effect modifies through the progression of the training. Moreover, it seems some regions are also influenced by the overall time of the experience.

Muge Karaman¹, Yi Sui^1,2, He Wang³, Richard L Magin², Yuhua H Li⁴, and Xiaohong Joe Zhou^1,5
1Center for MR Research, University of Illinois at Chicago, Chicago, IL, United States, ²Bioengineering, University of Illinois at Chicago, Chicago, IL, United States, ³Philips Research China, Shanghai, China, ⁴Radiology, Xinhua Hospital, Shanghai, China, ⁵Departments of Radiology, Neurosurgery, and Bioengineering, University of Illinois at Chicago, Chicago, IL, United States

Differentiation of low-grade and high-grade brain tumors with the use of non-invasive imaging methods is important for the planning of optimal treatment, especially for the pediatric brain tumors that can be difficult to biopsy. Diffusion heterogeneity that reflects the underlying tissue structures may not be accurately captured by a simple diffusion imaging technique that uses a mono-exponential diffusion model to produce an ADC value. In this study, we show that the diagnostic accuracy of differentiating low-grade and high-grade pediatric brain tumors can be improved by using continuous random walk diffusion model that provides a more complete description of heterogeneous structures.

Choukri Mekkaoui¹, Fabricio Pereira², William J Kostis³, and Marcel P Jackowski^4
1Harvard Medical School - Massachussetts General Hospital, Boston, MA, United States, ²CHU Nîmes, France, ³Harvard Medical School-Massachusetts General Hospital, Boston, MA, United States, ⁴University of São Paulo, São Paulo, Brazil

Diffusion Tensor Imaging (DTI) has been used extensively for the diagnosis and prognosis of cerebral lesions as well as for surgical planning. Traditional tensor representations, however, have difficulties in differentiating tumor-infiltrated regions and peritumoral edema. In this work, we employ the supertoroidal model of the diffusion tensor and the toroidal volume (TV) in the characterization of Glioblastoma multiforme (GBM). We show that the supertoroidal model is better suited to identifying the heterogeneity of structure in GBMs and that the nonlinear response of TV can enhance differentiation of gliomas from surrounding edema and normal brain parenchyma.

Jingjing Jiang¹ and Wenzhen Zhu^1
1Tongji hospital, tongji medical college, huazhong university of science and technology, Wuhan, Hubei, China

Diffusion wighted imaging (DWI) is one of the advanced neuroimaging techniques in the evaluation of brain tumors. Stretched exponential model DWI (SEM-DWI) is one of them which can properly describe the signal intensity decay when b-factor exceeds 1000 s/mm2. Proliferating cell nuclear antigen (PCNA) and Ki-67 are two of the common nuclear markers in proliferation activity evaluation. In this study, we will assess the feasibility of SEM-DWI in grading gliomas and to find the correlation between DWI parameters and PCNA and Ki-67 labeling index (LI) thus to evaluate DWI as a noninvasive technique for evaluating the proliferative characteristics of gliomas.

Silvia De Santis¹, Nicola Toschi^2,3, Derek K Jones¹, Claudio Lucetti⁴, Stefano Diciotti⁵, Marco Giannelli⁶, and Carlo Tessa^7
1CUBRIC Cardiff University, Cardiff, United Kingdom, ²Medical Physics Section, Department of Biomedicine and Prevention, Faculty of Medicine, University of Rome “Tor Vergata”, Italy, ³Department of Radiology, A.A. Martinos Center for Biomedical Imaging, MGH and Harvard Medical School, Boston, MA, United States, ⁴Division of Neurology Unit, Versilia Hospital, Lido di Camaiore (Lu), Italy, ⁵Department of Electrical, Electronic, and Information Engineering “Guglielmo Marconi”, University of Bologna, Cesena, Italy, ⁶Unit of Medical Physics, Pisa University Hospital “Azienda Ospedaliero-Universitaria Pisana”, Pisa, Italy, ⁷Division of Radiology Unit, Versilia Hospital, Lido di Camaiore (Lu), Italy

Parkinson's disease (PD) is associated with the death of dopamine-generating cells in the substantia nigra. We apply the composite hindered and restricted model of diffusion (CHARMED) and the stretched exponential model (SEM) to test the ability of multi-shell methods to differentiate between Parkinson's Disease (PD) patients and healthy controls. We found that multi-shell diffusion MRI provides significantly higher sensitivity and specificity to microstructural WM alterations in PD when compared to conventional DTI. Employing more advanced models such as CHARMED or SEM to study neurodegenerative pathologies may aid the interpretation of otherwise aspecific differences which can be detected with DTI.

Torben Schneider¹, Wallace Brownlee¹, Jonathan Clayden², Olga Ciccarelli³, David H Miller¹, Daniel C Alexander⁴, and Claudia A M Wheeler-Kingshott^1
1NMR Research Unit, Department of Neuroinflammation, Queen Square MS Centre, UCL Institute of Neurology, London, United Kingdom, ²UCL Institute of Child Health, Imaging & Biophysics Unit, London, United Kingdom, ³Brain Repair & Rehabilitation, UCL Institute of Neurology, London, United Kingdom,⁴Centre of Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom

It is known that microstructural changes in the Corpus Callosum are associated with disability in Multiple Sclerosis. Here, we have used a novel diffusion MRI protocol and analysis method to measure axon density and diameter in the Corpus Callosum in MS in-vivo and on a standard clinical scanner. Our preliminary results suggest a regional decrease of axon density and increase in axon diameter both in normal appearing white matter and lesion tissue, which is consistent with findings from ex vivo histology.