FC12-03 - DTI-based in vivo mapping of subregions within the human hypothalamus

2011 ◽  
Vol 26 (S2) ◽  
pp. 1878-1878
Author(s):  
P. Schoenknecht ◽  
A. Anwander ◽  
F. Petzold ◽  
S. Schindler ◽  
T. Knoesche ◽  
...  
Keyword(s):  
High Resolution ◽  
Behavioral Responses ◽  
Point Of View ◽  
Post Mortem ◽  
Similarity Matrix ◽  
Human Hypothalamus ◽  
Fine Grained ◽  
Clinical Point ◽  
Tissue Orientation

IntroductionThe hypothalamus is involved in many aspects of behavioral responses but parcellations of hypothalamic subnuclei have only been feasible in post-mortem brains. Thus it would be-from a clinical point of view-highly desirable if hypothalamic subnuclei could be delineated also noninvasively in living subjects. This study is a first step in this direction: We exploited the directionality information inherent in high-resolution DTI data to map subregions of the hypothalamus in healthy volunteers.directionality information using DTI data to map subregions of the hypothalamus.MethodsWe scanned 10 subjects with a Siemens 3 T scanner, acquired DTI and T1 scans. We computed the similarity of fiber orientations between all voxels and subjects, and clustered the similarity matrix in 3 regions using a k-means algorithm.ResultsThe diffusion images showed anisotropic tissue orientation within the hypothalamus which was consistent across subjects. The clustering in 3 regions resulted in an anatomically coherent arrangement of clusters across hemispheres and subjects. In each ROI, we found an anterior, a posteromedial, and a lateral subdivision with consistent microscopic tissue orientations across subjects.ConclusionThis is to our best knowledge the first study that demonstrates the fine-grained microstructural organization within the human hypothalamus noninvasively in living subjects.

High Resolution In Vivo and Post Mortem Atlas of the Human Thalamus

NeuroImage ◽  
1998 ◽  
Vol 7 (4) ◽  
pp. S712
Author(s):  
CJ Holmes ◽  
R Menon ◽  
K Negoro ◽  
T Peters ◽  
AW Toga
Keyword(s):  
High Resolution ◽  
Post Mortem ◽  
Human Thalamus

scholarly journals Mapping the Human Visual Thalamus and its Cytoarchitectonic Subdivisions Using Quantitative MRI

2020 ◽  
Author(s):  
Christa Müller-Axt ◽  
Cornelius Eichner ◽  
Henriette Rusch ◽  
Louise Kauffmann ◽  
Pierre-Louis Bazin ◽  
...  
Keyword(s):  
High Resolution ◽  
Visual Information ◽  
Quantitative Mri ◽  
7 Tesla ◽  
Post Mortem ◽  
Non Invasive ◽  
Visual Thalamus ◽  
Processing Site ◽  
The Brain

AbstractThe human lateral geniculate nucleus (LGN) of the visual thalamus is a key subcortical processing site for visual information analysis. A non-invasive assessment of the LGN and its functionally and microstructurally distinct magnocellular (M) and parvocellular (P) subdivisions in-vivo in humans is challenging, because of its small size and location deep inside the brain. Here we tested whether recent advances in high-field structural quantitative MRI (qMRI) can enable MR-based mapping of human LGN subdivisions. We employed ultra-high resolution 7 Tesla qMRI of a post-mortem human LGN specimen and high-resolution 7 Tesla in-vivo qMRI in a large participant sample. We found that a quantitative assessment of the LGN and a differentiation of its subdivisions was possible based on microstructure-informed MR-contrast alone. In both the post-mortem and in-vivo qMRI data, we identified two components of shorter and longer longitudinal relaxation time (T1) within the LGN that coincided with the known anatomical locations of a dorsal P and a ventral M subdivision, respectively. Through a subsequent ground truth histological examination of the same post-mortem LGN specimen, we showed that the observed T1 contrast pertains to cyto- and myeloarchitectonic differences between LGN subdivisions. These differences were based on cell and myelin density, but not on iron content. Our qMRI-based mapping strategy overcomes shortcomings of previous fMRI-based mapping approaches. It paves the way for an in-depth understanding of the function and microstructure of the LGN in humans. It also enables investigations into the selective contributions of LGN subdivisions to human behavior in health and disease.Significance StatementThe lateral geniculate nucleus (LGN) is a key processing site for the analysis of visual information. Due to its small size and deep location within the brain, non-invasive mapping of the LGN and its microstructurally distinct subdivisions in humans is challenging. Using quantitative MRI methods that are sensitive to underlying microstructural tissue features, we show that a differentiation of the LGN and its microstructurally distinct subdivisions is feasible in humans non-invasively. These findings are important because they open up novel opportunities to assess the hitherto poorly understood complex role of the LGN in human perception and cognition, as well as the contribution of selective LGN subdivision impairments to various clinical conditions including developmental dyslexia, glaucoma and multiple sclerosis.

scholarly journals High-resolution MRI: in vivo histology?

2005 ◽  
Vol 361 (1465) ◽  
pp. 137-146 ◽  
Author(s):  
Holly Bridge ◽  
Stuart Clare
Keyword(s):  
Magnetic Resonance Imaging ◽  
High Resolution ◽  
Post Mortem ◽  
Resonance Imaging ◽  
Brain Surface ◽  
High Resolution Mri ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain ◽  
Very High

For centuries scientists have been fascinated with the question of how the brain works. Investigators have looked at both where different functions are localized and how the anatomical microstructure varies across the brain surface. Here we discuss how advances in magnetic resonance imaging (MRI) have allowed in vivo visualization of the fine structure of the brain that was previously only visible in post-mortem brains. We present data showing the correspondence between definitions of the primary visual cortex defined anatomically using very high-resolution MRI and functionally using functional MRI. We consider how this technology can be applied to allow the investigation of brains that differ from normal, and what this ever-evolving technology may be able to reveal about in vivo brain structure in the next few years.

High-resolution electron microscopy of Cu2O surfaces

1986 ◽  
Vol 44 ◽  
pp. 396-397
Author(s):  
V. Castano ◽  
W. Krakow
Keyword(s):  
High Resolution ◽  
Natural Extension ◽  
High Resolution Electron Microscopy ◽  
Point Of View ◽  
Initial Oxidation ◽  
System A ◽  
Resolution Electron ◽  
Surface Reconstructions ◽  
Atomic Surface ◽  
Au Thin Films

In non-UHV microscope environments atomic surface structure has been observed for flat-on for various orientations of Au thin films and edge-on for columns of atoms in small particles. The problem of oxidation of surfaces has only recently been reported from the point of view of high resolution microscopy revealing surface reconstructions for the Ag2O system. A natural extension of these initial oxidation studies is to explore other materials areas which are technologically more significant such as that of Cu2O, which will now be described.

High Resolution Low Loss Microscopy of Crystalline Surfaces

1980 ◽  
Vol 38 ◽  
pp. 162-163
Author(s):  
William Krakow ◽  
Alec N. Broers
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Surface Topography ◽  
Secondary Electron ◽  
Objective Lens ◽  
Surface Imaging ◽  
Low Loss ◽  
Fine Grained ◽  
Scanning Electron ◽  
Crystalline Surfaces

Low-loss scanning electron microscopy can be used to investigate the surface topography of solid specimens and provides enhanced image contrast over secondary electron images. A high resolution-condenser objective lens has allowed the low-loss technique to resolve separations of Au nucleii of 50Å and smaller dimensions of 25Å in samples coated with a fine grained carbon-Au-palladium layer. An estimate of the surface topography of fine grained vapor deposited materials (20 - 100Å) and the surface topography of underlying single crystal Si in the 1000 - 2000Å range has also been investigated. Surface imaging has also been performed on single crystals using diffracted electrons scattered through 10−2 rad in a conventional TEM. However, severe tilting of the specimen is required which degrades the resolution 15 to 100 fold due to image forshortening.

Theoretical And Practical Design Considerations for Ultra-High Resolution Electron Lenses

1980 ◽  
Vol 38 ◽  
pp. 266-269
Author(s):  
Y. Harada ◽  
K. Tsuno ◽  
Y. Arai
Keyword(s):  
Optical Properties ◽  
High Resolution ◽  
Chromatic Aberration ◽  
Point Of View ◽  
Pole Piece ◽  
Axial Field ◽  
Design Considerations ◽  
Resolution Electron ◽  
Practical Design ◽  
Peak Flux

Magnetic objective lenses, from the point of view of pole piece geometry, can he roughly classified into two types, viz., symmetrical and asymmetrical. In the case of the former, the optical properties have been calculated by several authors1-3) and the results would appear to suggest that, in order to reduce the spherical and chromatic aberration coefficients, Cs and Cc, it is necessary to decrease the half-width value of the axial field distribution and to increase the peak flux density. The expressions for either minimum Cs or minimum Cc were presented in the form of ‘universal’ curves by Mulvey and Wallington4).

Ground state molecular parameters of phosphine, PH3, from the simultaneous analysis of the high-resolution infrared, microwave and submillimeterwave spectra

1985 ◽  
Vol 50 (11) ◽  
pp. 2480-2492 ◽  
Author(s):  
Soňa Přádná ◽  
Dušan Papoušek ◽  
Jyrki Kauppinen ◽  
Sergei P. Belov ◽  
Andrei F. Krupnov ◽  
...  
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Ground State ◽  
Unitary Transformation ◽  
Point Of View ◽  
Acoustic Detection ◽  
Molecular Parameters ◽  
Microwave Spectrometer ◽  
Fourier Transform Spectra ◽  
First Time

Fourier transform spectra of the ν2 band of PH3 have been remeasured with 0.0045 cm-1 resolution. Ground state combination differences from these data have been fitted simultaneously with the microwave and submillimeterwave data to determine the ground state spectroscopical parameters of PH3 including the parameters of the Δk = ± 3n interactions. The correlation between the latter parameters has been discussed from the point of view of the existence of two equivalent effective rotational operators which are related by a unitary transformation. The ΔJ = 0, +1, ΔK = 0 (A1 ↔ A2, E ↔ E) rotational transitions in the ν2 and ν4 states have been measured for the first time by using a microwave spectrometer and a radiofrequency spectrometer with acoustic detection.

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