Wilbrand knee

Shin, Ryan; Qureshi, R. A.; Harris, Natalie R.; Bakar, D.; Li, Tuo Peter; Jafri, M. Saleet; Tang, Cha‐Min

doi:10.1212/wnl.0000000000000084

Cited by 17 publications

(16 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The authors made thin (25 μm) sections of the chiasm, which were then illuminated and digitally imaged from different angles. Whereas superior chiasm sections showed no curving of crossing fibers, in the inferior chiasm sections, there was a sheet of crossing fibers from the anterior chiasm that bends towards the contralateral optic nerve before arching back towards the optic tract, consistent with the original description of Wilbrand [5].Recently, a team of scientists from University of Maryland and Georgetown University has proved on four human optic chiasms and three monkey chiasms, that in all four human optic chiasms, there are thin fiber tracts consistent with those Wilbrand had described and no such tracts were found in three monkey chiasms, concluding that Wilbrand's knee exists in humans and are not found in the monkeys [3]. Moreover, the authors believe that their results could explain the conflicting reports in the literature regarding its existence.…”

supporting

confidence: 82%

To be or not to be Wilbrand’s knee? A question that is looking for an answer

et al. 2018

View full text Add to dashboard Cite

Dear Editor:We would very much like to thank the authors for their review of our paper and for the interesting query, which was quite insightful.First of all, indeed, Horton demonstrated that optic nerve fibers cross the optic chiasm without entering to the contralateral optic nerve [2], and this study was completed by Lee et al. on humans undergoing surgery to divide the optic nerve at the optic nervechiasm junction [4]. Based on our knowledge, these two studies are among the few which contest the existence of Wilbrand knee, believing it to be an artifact secondary to enucleation.In 2014, Shin et al. managed to prove the existence of the Wilbrand knee by using the anisotropic light-reflecting properties of myelinated axons. The authors made thin (25 μm) sections of the chiasm, which were then illuminated and digitally imaged from different angles. Whereas superior chiasm sections showed no curving of crossing fibers, in the inferior chiasm sections, there was a sheet of crossing fibers from the anterior chiasm that bends towards the contralateral optic nerve before arching back towards the optic tract, consistent with the original description of Wilbrand [5].Recently, a team of scientists from University of Maryland and Georgetown University has proved on four human optic chiasms and three monkey chiasms, that in all four human optic chiasms, there are thin fiber tracts consistent with those Wilbrand had described and no such tracts were found in three monkey chiasms, concluding that Wilbrand's knee exists in humans and are not found in the monkeys [3]. Moreover, the authors believe that their results could explain the conflicting reports in the literature regarding its existence.Even if his eponymic knee was disputed by modern time neuroanatomy techniques, Wilbrand's writings have anticipated the organization of visual cortex and the concept of ocular dominance columns, and even if this structure might not exist, it probably remains a functionally important and significant concept [1] worth remembering.We believe that the distinguished professor of ophthalmology Hermann Wilbrand (1851Wilbrand ( -1935 is worth remembering in any work about the history of neuro-ophthalmology, not only for his knee-a functionally significant concept-but also for his monumental work and for what he represents: one of the starting points of modern neuro-ophthalmology. The anatomical and neuroimaging studies on optic chiasm must continue, because they shall throw light on the Wilbrand knee.We again would like to thank the authors for taking the time to write us and provide these useful comments and insights into our paper.

show abstract

supporting

confidence: 82%

To be or not to be Wilbrand’s knee? A question that is looking for an answer

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Thus, sources above and beyond MRI may be needed to refine definition on the anatomy layer. To this end, techniques like polarized light imaging (Axer et al, 2011) or anisotropic scattering imaging (Shin et al, 2014) as well as the registration of histological stacks into template space (Alho et al, 2017; Amunts et al, 2013; Chakravarty et al, 2006; Ewert et al, 2018b; Forstmann et al, 2016; Jakab et al, 2012; Yelnik et al, 2007) are already applied increasingly.…”

Section: Discussionmentioning

confidence: 99%

Lead-DBS v2: Towards a comprehensive pipeline for deep brain stimulation imaging

et al. 2019

View full text Add to dashboard Cite

Deep brain stimulation (DBS) is a highly efficacious treatment option for movement disorders and a growing number of other indications are investigated in clinical trials. To ensure optimal treatment outcome, exact electrode placement is required. Moreover, to analyze the relationship between electrode location and clinical results, a precise reconstruction of electrode placement is required, posing specific challenges to the field of neuroimaging. Since 2014 the open source toolbox Lead-DBS is available, which aims at facilitating this process. The tool has since become a popular platform for DBS imaging. With support of a broad community of researchers worldwide, methods have been continuously updated and complemented by new tools for tasks such as multispectral nonlinear registration, structural / functional connectivity analyses, brain shift correction, reconstruction of microelectrode recordings and orientation detection of segmented DBS leads. The rapid development and emergence of these methods in DBS data analysis require us to revisit and revise the pipelines introduced in the original methods publication. Here we demonstrate the updated DBS and connectome pipelines of Lead-DBS using a single patient example with state-of-the-art high-field imaging as well as a retrospective cohort of patients scanned in a typical clinical setting at 1.5T. Imaging data of the 3T example patient is co-registered using five algorithms and nonlinearly warped into template space using ten approaches for comparative purposes. After reconstruction of DBS electrodes (which is possible using three methods and a specific refinement tool), the volume of tissue activated is calculated for two DBS settings using four distinct models and various parameters. Finally, four whole-brain tractography algorithms are applied to the patient’s preoperative diffusion MRI data and structural as well as functional connectivity between the stimulation volume and other brain areas are estimated using a total of eight approaches and datasets. In addition, we demonstrate impact of selected preprocessing strategies on the retrospective sample of 51 PD patients. We compare the amount of variance in clinical improvement that can be explained by the computer model depending on the method of choice. This work represents a multi-institutional collaborative effort to develop a comprehensive, open source pipeline for DBS imaging and connectomics, which has already empowered several studies, and may facilitate a variety of future studies in the field.

show abstract

“…In 2014, Shin and colleagues (17) reported evidence for Wilbrand's knee in the normal human optic chiasm. This finding garnered considerable attention because never before had the knee been shown in normal human autopsy specimens.…”

Section: Imaging the Unlabeled Optic Chiasmmentioning

confidence: 99%

Wilbrand's Knee: To Be or Not to Be a Knee?

Horton

2020

Journal of Neuro-Ophthalmology

View full text Add to dashboard Cite

Wilbrand's knee of the optic chiasm refers to crossing fibers from one optic nerve that stray for a short distance into the opposite optic nerve before joining the optic tract. This loop of aberrant axons, although small, has generated much controversy. In a previous study, labeling of the optic pathway in normal monkeys with a radioactive tracer revealed no Wilbrand's knee. Monocular enucleation induced a typical knee to form. These findings suggested that Wilbrand's knee is absent normally, but appears after atrophy of one optic nerve. This conclusion has been challenged by images showing Wilbrand's knee in the normal human chiasm using anisotropic light scattering. It has also been resisted by some clinicians who believe that Wilbrand's knee is necessary to explain the anterior chiasmal syndrome. Early in his distinguished career, William F. Hoyt examined the fiber organization of the monkey optic nerve and chiasm. He found no evidence for Wilbrand's knee and rejected its importance for the topical diagnosis of chiasmal lesions. His conclusion is supported by new data showing that anisotropic light scattering is not a reliable method for tracing axons. Hence, that method has given a misleading impression that Wilbrand's knee exists in normal subjects. Although Wilbrand's knee has fascinated neuro ophthalmologists for more than a century, it is an inconsequential structure that develops only after a longstanding monocular optic neuropathy.

show abstract

Wilbrand knee

Cited by 17 publications

References 0 publications

To be or not to be Wilbrand’s knee? A question that is looking for an answer

To be or not to be Wilbrand’s knee? A question that is looking for an answer

Lead-DBS v2: Towards a comprehensive pipeline for deep brain stimulation imaging

Wilbrand's Knee: To Be or Not to Be a Knee?

Contact Info

Product

Resources

About