In vivo 3D Reconstruction of the Human Pallidothalamic and Nigrothalamic Pathways With Super-Resolution 7T MR Track Density Imaging and Fiber Tractography

The output network of the basal ganglia plays an important role in motor, associative, and limbic processing and is generally characterized by the pallidothalamic and nigrothalamic pathways. However, these connections in the human brain remain difficult to elucidate because of the resolution limit of current neuroimaging techniques. The present study aimed to investigate the mesoscopic nature of these connections between the thalamus, substantia nigra pars reticulata, and globus pallidus internal segment using 7 Tesla (7T) magnetic resonance imaging (MRI). In this study, track-density imaging (TDI) of the whole human brain was employed to overcome the limitations of observing the pallidothalamic and nigrothalamic tracts. Owing to the super-resolution of the TD images, the substructures of the SN, as well as the associated tracts, were identified. This study demonstrates that 7T MRI and MR tractography can be used to visualize anatomical details, as well as 3D reconstruction, of the output projections of the basal ganglia.

Download Full-text

Papez Circuit Observed by in vivo Human Brain With 7.0T MRI Super-Resolution Track Density Imaging and Track Tracing

Frontiers in Neuroanatomy ◽

10.3389/fnana.2019.00017 ◽

2019 ◽

Vol 13 ◽

Cited By ~ 7

Author(s):

Sang-Han Choi ◽

Young-Bo Kim ◽

Sun-Ha Paek ◽

Zang-Hee Cho

Keyword(s):

Human Brain ◽

Super Resolution ◽

Track Density ◽

Papez Circuit

Download Full-text

Meyer’s Loop Anatomy Demonstrated Using Diffusion Tensor MR Imaging and Fiber Tractography at 3T

Acta Medica Marisiensis ◽

10.2478/amma-2014-0045 ◽

2014 ◽

Vol 60 (5) ◽

pp. 215-222 ◽

Cited By ~ 1

Author(s):

Cristina Goga ◽

Zeynep Firat ◽

Klara Brinzaniuc ◽

Is Florian

Keyword(s):

Diffusion Tensor Imaging ◽

Diffusion Tensor ◽

Region Of Interest ◽

Fiber Tractography ◽

Brain Images ◽

3 Dimensional ◽

Software Release ◽

Magnetic Resonance Imaging Mri ◽

Meyer’S Loop

Abstract Objective: The ultimate anatomy of the Meyer’s loop continues to elude us. Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) may be able to demonstrate, in vivo, the anatomy of the complex network of white matter fibers surrounding the Meyer’s loop and the optic radiations. This study aims at exploring the anatomy of the Meyer’s loop by using DTI and fiber tractography. Methods: Ten healthy subjects underwent magnetic resonance imaging (MRI) with DTI at 3 T. Using a region-of-interest (ROI) based diffusion tensor imaging and fiber tracking software (Release 2.6, Achieva, Philips), sequential ROI were placed to reconstruct visual fibers and neighboring projection fibers involved in the formation of Meyer’s loop. The 3-dimensional (3D) reconstructed fibers were visualized by superimposition on 3-planar MRI brain images to enhance their precise anatomical localization and relationship with other anatomical structures. Results: Several projection fiber including the optic radiation, occipitopontine/parietopontine fibers and posterior thalamic peduncle participated in the formation of Meyer’s loop. Two patterns of angulation of the Meyer’s loop were found. Conclusions: DTI with DTT provides a complimentary, in vivo, method to study the details of the anatomy of the Meyer’s loop.

Download Full-text

Taste quality representation in the human brain

10.1101/726711 ◽

2019 ◽

Author(s):

Jason A. Avery ◽

Alexander G. Liu ◽

John E. Ingeholm ◽

Cameron D. Riddell ◽

Stephen J. Gotts ◽

...

Keyword(s):

Human Brain ◽

Cortical Neurons ◽

Brain Regions ◽

Taste Quality ◽

7 Tesla ◽

Mammalian Brain ◽

High Magnetic Field Strength ◽

Magnetic Resonance Imaging Mri ◽

Spatial Locations ◽

Univariate Analyses

SUMMARYIn the mammalian brain, the insula is the primary cortical substrate involved in the perception of taste. Recent imaging studies in rodents have identified a gustotopic organization in the insula, whereby distinct insula regions are selectively responsive to one of the five basic tastes. However, numerous studies in monkeys have reported that gustatory cortical neurons are broadly-tuned to multiple tastes, and tastes are not represented in discrete spatial locations. Neuroimaging studies in humans have thus far been unable to discern between these two models, though this may be due to the relatively low spatial resolution employed in taste studies to date. In the present study, we examined the spatial representation of taste within the human brain using ultra-high resolution functional magnetic resonance imaging (MRI) at high magnetic field strength (7-Tesla). During scanning, participants tasted sweet, salty, sour and tasteless liquids, delivered via a custom-built MRI-compatible tastant-delivery system. Our univariate analyses revealed that all tastes (vs. tasteless) activated primary taste cortex within the bilateral dorsal mid-insula, but no brain region exhibited a consistent preference for any individual taste. However, our multivariate searchlight analyses were able to reliably decode the identity of distinct tastes within those mid-insula regions, as well as brain regions involved in affect and reward, such as the striatum, orbitofrontal cortex, and amygdala. These results suggest that taste quality is not represented topographically, but by a combinatorial spatial code, both within primary taste cortex as well as regions involved in processing the hedonic and aversive properties of taste.

Download Full-text

Mapping Short Association Fibers in the Early Cortical Visual Processing Stream Using In Vivo Diffusion Tractography

Cerebral Cortex ◽

10.1093/cercor/bhaa049 ◽

2020 ◽

Vol 30 (8) ◽

pp. 4496-4514 ◽

Cited By ~ 5

Author(s):

Fakhereh Movahedian Attar ◽

Evgeniya Kirilina ◽

Daniel Haenelt ◽

Kerrin J Pine ◽

Robert Trampel ◽

...

Keyword(s):

Human Brain ◽

Visual Processing ◽

Repeated Measurements ◽

Fiber Tractography ◽

Cortical Areas ◽

Brain Connectome ◽

Cortical Visual Processing ◽

Association Fibers ◽

Fiber Connectivity

Abstract Short association fibers (U-fibers) connect proximal cortical areas and constitute the majority of white matter connections in the human brain. U-fibers play an important role in brain development, function, and pathology but are underrepresented in current descriptions of the human brain connectome, primarily due to methodological challenges in diffusion magnetic resonance imaging (dMRI) of these fibers. High spatial resolution and dedicated fiber and tractography models are required to reliably map the U-fibers. Moreover, limited quantitative knowledge of their geometry and distribution makes validation of U-fiber tractography challenging. Submillimeter resolution diffusion MRI—facilitated by a cutting-edge MRI scanner with 300 mT/m maximum gradient amplitude—was used to map U-fiber connectivity between primary and secondary visual cortical areas (V1 and V2, respectively) in vivo. V1 and V2 retinotopic maps were obtained using functional MRI at 7T. The mapped V1–V2 connectivity was retinotopically organized, demonstrating higher connectivity for retinotopically corresponding areas in V1 and V2 as expected. The results were highly reproducible, as demonstrated by repeated measurements in the same participants and by an independent replication group study. This study demonstrates a robust U-fiber connectivity mapping in vivo and is an important step toward construction of a more complete human brain connectome.

Download Full-text

In vivo detection of serine in the human brain by proton magnetic resonance spectroscopy (1 H-MRS) at 7 Tesla

Magnetic Resonance in Medicine ◽

10.1002/mrm.22079 ◽

2009 ◽

Vol 62 (4) ◽

pp. 1042-1046 ◽

Cited By ~ 21

Author(s):

Changho Choi ◽

Ivan Dimitrov ◽

Deborah Douglas ◽

Chenguang Zhao ◽

Halima Hawesa ◽

...

Keyword(s):

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

Human Brain ◽

Proton Magnetic Resonance ◽

Proton Magnetic Resonance Spectroscopy ◽

7 Tesla ◽

Resonance Spectroscopy ◽

In Vivo Detection

Download Full-text

Euclidean distance as a measure to distinguish ventral and dorsal white matter connectivity in the human brain

10.1101/053959 ◽

2016 ◽

Author(s):

Philipp Kellmeyer ◽

Magnus-Sebastian Vry

Keyword(s):

White Matter ◽

Human Brain ◽

Cognitive Processing ◽

Euclidean Distance ◽

Large Scale ◽

Diffusion Tensor ◽

Large Body ◽

Coordinate Space ◽

Fiber Tractography

AbstractFiber tractography based on diffusion tensor imaging (DTI) has become an important research tool for investigating the anatomical connectivity between brain regions in vivo. Combining DTI with functional magnetic resonance imaging (fMRI) allows for the mapping of structural and functional architecture of large-scale networks for cognitive processing. This line of research has shown that ventral and dorsal fiber pathways subserve different aspects of bottom-up- and top-down processing in the human brain.Here, we investigate the feasibility and applicability of Euclidean distance as a simple geometric measure to differentiate ventral and dorsal long-range white matter fiber pathways tween parietal and inferior frontal cortical regions, employing a body of studies that used probabilistic tractography.We show that ventral pathways between parietal and inferior frontal cortex have on average a significantly longer Euclidean distance in 3D-coordinate space than dorsal pathways. We argue that Euclidean distance could provide a simple measure and potentially a boundary value to assess patterns of connectivity in fMRI studies. This would allow for a much broader assessment of general patterns of ventral and dorsal large-scale fiber connectivity for different cognitive operations in the large body of existing fMRI studies lacking additional DTI data.

Download Full-text

High resolution atlas of the venous brain vasculature from 7 T quantitative susceptibility maps

10.1101/444349 ◽

2018 ◽

Author(s):

Julia Huck ◽

Yvonne Wanner ◽

Audrey P. Fan ◽

Anna-Thekla Jäger ◽

Sophia Grahl ◽

...

Keyword(s):

Human Brain ◽

Blood Oxygen Level Dependent ◽

7 Tesla ◽

Cerebral Vein ◽

Registration Method ◽

Isotropic Resolution ◽

Common Location ◽

Susceptibility Maps ◽

Venous Vasculature

AbstractThe vascular organization of the human brain can determine neurological and neurophysiological functions, yet thus far it has not been comprehensively mapped. Aging and diseases such as dementia are known to be associated with changes to the vasculature and normative data could help detect these vascular changes in neuroimaging studies. Furthermore, given the well-known impact of venous vessels on the blood oxygen level dependent (BOLD) signal, information about the common location of veins could help detect biases in existing datasets. In this work, a quantitative atlas of the venous vasculature using quantitative susceptibility maps (QSM) acquired with a 0.6 mm isotropic resolution is presented. The Venous Neuroanatomy (VENAT) atlas was created from 5 repeated 7 Tesla MRI measurements in young and healthy volunteers (n = 20, 10 females, mean age = 25.1 ± 2.5 years) using a two-step registration method on 3D segmentations of the venous vasculature. This cerebral vein atlas includes the average vessel location, diameter (mean: 0.84 ± 0.33 mm) and curvature (0.11 ± 0.05 mm−1) from all participants and provides an in vivo measure of the angio-architectonic organization of the human brain and its variability. This atlas can be used as a basis to understand changes in the vasculature during aging and neurodegeneration, as well as vascular and physiological effects in neuroimaging.

Download Full-text

The Spectrum of MR Detectable Cortical Microinfarcts: A Classification Study with 7-Tesla Postmortem MRI and Histopathology

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2014.258 ◽

2015 ◽

Vol 35 (4) ◽

pp. 676-683 ◽

Cited By ~ 37

Author(s):

Susanne J van Veluw ◽

Jaco JM Zwanenburg ◽

Annemieke JM Rozemuller ◽

Peter R Luijten ◽

Wim GM Spliet ◽

...

Keyword(s):

Brain Slices ◽

7 Tesla ◽

Perivascular Spaces ◽

Postmortem Mri ◽

Mri Features ◽

Mri Protocol ◽

Magnetic Resonance Imaging Mri ◽

Mri Evaluation ◽

Rating Criteria

Cerebral microinfarcts (CMIs) are common neuropathologic findings in aging and dementia. We explored the spectrum of cortical CMIs that can be visualized with 7T magnetic resonance imaging (MRI). Thirty-three coronal brain slices of 11 individuals with neuropathologically confirmed dementia were subjected to a high-resolution postmortem 7T MRI protocol. First, we identified all visible small (5 mm) intracortical and juxtacortical lesions on postmortem MRI. Lesions were classified as CMI or nonCMI based on histology, and their MR features were recorded. Thirty lesions were identified on the initial MRI evaluation, of which twenty-three could be matched with histology. Histopathology classified 12 lesions as CMIs, all of which were located intracortically. On the basis of their MR features, they could be classified as chronic gliotic CMIs—with or without cavitation or hemorrhagic components—and acute CMIs. Eleven MRI identified lesions were not of ischemic nature and most commonly enlarged or atypically shaped perivascular spaces. Their MRI features were similar to gliotic CMIs with or without cavitation, but these ‘CMI mimics’ were always located juxtacortically. 7T postmortem MRI distinguishes different histopathologic types of cortical CMIs, with distinctive MR characteristics. On the basis of our findings, we propose in vivo rating criteria for the detection of intracortical CMIs.

Download Full-text