The human hippocampus at 7 T-In vivo MRI

Hippocampus ◽  
2009 ◽  
Vol 19 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Jens M. Theysohn ◽  
O. Kraff ◽  
S. Maderwald ◽  
M.U. Schlamann ◽  
A. de Greiff ◽  
...  
Keyword(s):  
Human Hippocampus

A new method for the in vivo volumetric measurement of the human hippocampus with high neuroanatomical accuracy

Hippocampus ◽  
2000 ◽  
Vol 10 (6) ◽  
pp. 752-758 ◽  
Author(s):  
J. Pantel ◽  
D. S. O'Leary ◽  
K. Cretsinger ◽  
H. J. Bockholt ◽  
H. Keefe ◽  
...  
Keyword(s):  
New Method ◽  
Volumetric Measurement ◽  
Human Hippocampus

scholarly journals Ultra-high resolution in-vivo 7.0 T structural imaging of the human hippocampus reveals the endfolial pathway

NeuroImage ◽  
2015 ◽  
Vol 112 ◽  
pp. 1-6 ◽  
Author(s):  
Mansi B. Parekh ◽  
Brian K. Rutt ◽  
Ryan Purcell ◽  
Yuanxin Chen ◽  
Michael M. Zeineh
Keyword(s):  
High Resolution ◽  
Structural Imaging ◽  
Human Hippocampus

scholarly journals High-resolution 7T MRI of the human hippocampus in vivo

2008 ◽  
Vol 28 (5) ◽  
pp. 1266-1272 ◽  
Author(s):  
Bradley P. Thomas ◽  
E. Brian Welch ◽  
Blake D. Niederhauser ◽  
William O. Whetsell ◽  
Adam W. Anderson ◽  
...  
Keyword(s):  
High Resolution ◽  
Human Hippocampus

scholarly journals Anatomical and microstructural determinants of hippocampal subfield functional connectome embedding

2018 ◽  
Vol 115 (40) ◽  
pp. 10154-10159 ◽  
Author(s):  
Reinder Vos de Wael ◽  
Sara Larivière ◽  
Benoît Caldairou ◽  
Seok-Jun Hong ◽  
Daniel S. Margulies ◽  
...  
Keyword(s):  
Resting State ◽  
State Of The Art ◽  
Model System ◽  
Hippocampal Subfields ◽  
Functional Connectome ◽  
Human Hippocampus ◽  
Complex Anatomy ◽  
Robust Evidence ◽  
Anterior Posterior

The hippocampus plays key roles in cognition and affect and serves as a model system for structure/function studies in animals. So far, its complex anatomy has challenged investigations targeting its substructural organization in humans. State-of-the-art MRI offers the resolution and versatility to identify hippocampal subfields, assess its microstructure, and study topographical principles of its connectivity in vivo. We developed an approach to unfold the human hippocampus and examine spatial variations of intrinsic functional connectivity in a large cohort of healthy adults. In addition to mapping common and unique connections across subfields, we identified two main axes of subregional connectivity transitions. An anterior/posterior gradient followed long-axis landmarks and metaanalytical findings from task-based functional MRI, while a medial/lateral gradient followed hippocampal infolding and correlated with proxies of cortical myelin. Findings were consistent in an independent sample and highly stable across resting-state scans. Our results provide robust evidence for long-axis specialization in the resting human hippocampus and suggest an intriguing interplay between connectivity and microstructure.

Transcriptome-To-Metabolome™ Biosimulation Reveals Human Hippocampal Hypometabolism with Age and Alzheimer’s Disease

2011 ◽  
Vol 2 (2) ◽  
pp. 1-18
Author(s):  
Clyde F. Phelix ◽  
Richard G. LeBaron ◽  
Dawnlee J. Roberson ◽  
Rosa E. Villanueva ◽  
Greg Villareal ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Lipid Metabolism ◽  
Metabolic Pathways ◽  
Cholesterol Metabolism ◽  
Aging Male ◽  
Glucose And Lipid Metabolism ◽  
Human Hippocampus ◽  
Molecular Studies

The authors had validated a proprietary method, Transcriptome-To-Metabolome™ (TTM™) Biosimulation, for using the transcriptome to determine parameters for kinetic biosimulation of 16 core metabolic pathways. In vivo and in silico evidence confirmed that hippocampal cholesterol metabolism decreases with aging and increases with Alzheimer’s disease (AD). The molecular studies on aging primate and human hippocampus, including AD samples, provided internal validations on the biosimulations, while evidence from the literature, bibliome, provided external validations. This study extends the investigations with the TTM™ Biosimulations into the changes in these 16 metabolic pathways in aging male human hippocampus and for stages of AD. The authors report robust hippocampal hypometabolism in the fifth to tenth decade of life involving glucose and lipid metabolism in male humans. These findings are validated externally from the bibliome. Several changes in AD are demonstrated to be exaggerations or deviations of very late stage changes of normal aging among these pathways.

scholarly journals Segmenting subregions of the human hippocampus on structural magnetic resonance image scans: An illustrated tutorial

2017 ◽  
Vol 1 ◽  
pp. 239821281770144 ◽  
Author(s):  
Marshall A. Dalton ◽  
Peter Zeidman ◽  
Daniel N. Barry ◽  
Elaine Williams ◽  
Eleanor A. Maguire
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Magnetic Resonance Image ◽  
Magnetic Resonance Images ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Imaging Studies ◽  
Human Hippocampus ◽  
Cornu Ammonis

Background: The hippocampus plays a central role in cognition, and understanding the specific contributions of its subregions will likely be key to explaining its wide-ranging functions. However, delineating substructures within the human hippocampus in vivo from magnetic resonance image scans is fraught with difficulties. To our knowledge, the extant literature contains only brief descriptions of segmentation procedures used to delineate hippocampal subregions in magnetic resonance imaging/functional magnetic resonance imaging studies. Methods: Consequently, here we provide a clear, step-by-step and fully illustrated guide to segmenting hippocampal subregions along the entire length of the human hippocampus on 3T magnetic resonance images. Results: We give a detailed description of how to segment the hippocampus into the following six subregions: dentate gyrus/Cornu Ammonis 4, CA3/2, CA1, subiculum, pre/parasubiculum and the uncus. Importantly, this in-depth protocol incorporates the most recent cyto- and chemo-architectural evidence and includes a series of comprehensive figures which compare slices of histologically stained tissue with equivalent 3T images. Conclusion: As hippocampal subregion segmentation is an evolving field of research, we do not suggest this protocol is definitive or final. Rather, we present a fully explained and expedient method of manual segmentation which remains faithful to our current understanding of human hippocampal neuroanatomy. We hope that this ‘tutorial’-style guide, which can be followed by experts and non-experts alike, will be a practical resource for clinical and research scientists with an interest in the human hippocampus.

scholarly journals Hippocampal subfields revealed through unfolding and unsupervised clustering of laminar and morphological features in 3D BigBrain

2019 ◽  
Author(s):  
J. DeKraker ◽  
J.C. Lau ◽  
K.M. Ferko ◽  
A.R. Khan ◽  
S. Köhler
Keyword(s):  
Internal Structure ◽  
Ground Truth ◽  
Longitudinal Axis ◽  
Unsupervised Clustering ◽  
Morphological Features ◽  
Unique Combination ◽  
Hippocampal Subfields ◽  
Human Hippocampus ◽  
Hippocampal Structure

AbstractThe internal structure of the human hippocampus is challenging to map using histology or neuroimaging due to its complex archicortical folding. Here, we aimed to overcome this challenge using a unique combination of three methods. First, we leveraged a histological dataset with unprecedented 3D coverage, 3D BigBrain. Second, we imposed a computational unfolding framework that respects the topological continuity of hippocampal subfields, which are traditionally defined by laminar composition. Third, we adapted neocortical parcellation techniques to map the hippocampus with respect to not only laminar but also morphological features. Unsupervised clustering of these features revealed subdivisions that closely resemble ground-truth manual subfield segmentations. Critically, we also show that morphological features alone are sufficient to derive most hippocampal subfield boundaries. Moreover, some features showed differences within subfields along the hippocampal longitudinal axis. Our findings highlight new characteristics of internal hippocampal structure, and offer new avenues for its characterization with in-vivo neuroimaging.

High resolution in-vivo diffusion imaging of the human hippocampus

NeuroImage ◽  
2018 ◽  
Vol 182 ◽  
pp. 479-487 ◽  
Author(s):  
Sarah Treit ◽  
Trevor Steve ◽  
Donald W. Gross ◽  
Christian Beaulieu
Keyword(s):  
High Resolution ◽  
Diffusion Imaging ◽  
Human Hippocampus

scholarly journals Building a high-resolution in vivo minimum deformation average model of the human hippocampus

2017 ◽  
Author(s):  
Nina Jacobsen ◽  
Julie Broni Munk ◽  
Maciej Plocharski ◽  
Lasse Riis Østergaard ◽  
Lars Marstaller ◽  
...  
Keyword(s):  
High Resolution ◽  
Spin Echo ◽  
Turbo Spin Echo ◽  
Matching Algorithm ◽  
Turbo Spin ◽  
Human Hippocampus ◽  
Non Linear ◽  
Minimum Deformation ◽  
Contrast Matching

AbstractObjectiveMinimum deformation averaging (MDA) procedures exploit the information contained in inter-individual variations to generate high-resolution, high-contrast models through iterative model building. However, MDA models built from different image contrasts reside in disparate spaces and their complementary information cannot be utilized easily. The aim of this work was to develop an algorithm for the non-linear alignment of two MDA models with different contrasts to create a high-resolution in vivo model of the human hippocampus with a spatial resolution of 300 μm.MethodsA Turbo Spin Echo MDA model covering the hippocampus was contrast matched to a whole-brain MP2RAGE MDA model and aligned using cross-correlation and non-linear transformation. The contrast matching algorithm followed a global voxel location-based approach to estimate the relationship between intensity values of the two models. The performance of the algorithm was evaluated by comparing it to a non-linear registration obtained using mutual information without contrast matching. The complimentary information from both contrasts was then utilized in an automated hippocampal subfield segmentation pipeline.ResultsThe contrast of the Turbo Spin Echo MDA model could successfully be matched to the MP2RAGE MDA model. Registration using cross correlation provided more accurate alignment of the models compared to a mutual information based approach. The segmentation using ASHS resulted in hippocampal subfield delineations that resembled the tissue boundaries observed in the Turbo Spin Echo MDA model.ConclusionThe developed contrast matching algorithm facilitated the creation of a high-resolution multi-modal in vivo MDA model of the human hippocampus. This model can be used to improve algorithms for hippocampal subfield segmentation and could potentially support the early detection of neurodegenerative diseases.

scholarly journals Anatomical connectivity along the anterior-posterior axis of the human hippocampus: new insights using quantitative fibre-tracking.

2021 ◽  
Author(s):  
Marshall Axel Dalton ◽  
Arkiev D'Souza ◽  
Jinglei Lv ◽  
Fernando Calamante
Keyword(s):  
Memory Systems ◽  
Brain Regions ◽  
Heterogeneous Structure ◽  
Major Advance ◽  
Anatomical Connectivity ◽  
Cortical Areas ◽  
Human Hippocampus ◽  
Anterior Posterior ◽  
Anterior Posterior Axis

The hippocampus supports multiple cognitive functions including episodic memory. Recent work has highlighted functional differences along the anterior-posterior axis of the human hippocampus but the neuroanatomical underpinnings of these differences remain unclear. We leveraged track-density imaging to systematically examine anatomical connectivity between the cortical mantle and the anterior-posterior axis of the in-vivo human hippocampus. We first identified the most highly connected cortical areas and detailed the degree to which they preferentially connect along the anterior-posterior axis of the hippocampus. Then, using a tractography pipeline specifically tailored to measure the location and density of streamline endpoints within the hippocampus, we characterised where, within the hippocampus, these cortical areas preferentially connect. Our results were striking in showing that different parts of the hippocampus preferentially connect with distinct cortical areas. Furthermore, we provide evidence that both gradients and circumscribed areas of dense extrinsic anatomical connectivity exist within the human hippocampus. These findings inform conceptual debates in the field by unveiling how specific regions along the anterior-posterior axis of the hippocampus are associated with different cortical inputs/outputs. Overall, our results represent a major advance in our ability to map the anatomical connectivity of the human hippocampus in-vivo and inform our understanding of the neural architecture of hippocampal dependent memory systems in the human brain. This detailed characterization of how specific portions of the hippocampus anatomically connect with cortical brain regions may promote a better understanding of its role in cognition and we emphasize the importance of considering the hippocampus as a heterogeneous structure.

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