Coordinate System of Three-Semicircular Canals.

Yasuko Arai

doi:10.3757/jser.61.391

Interstitial Nucleus of Cajal Encodes Three-Dimensional Head Orientations in Fick-Like Coordinates

Journal of Neurophysiology ◽

10.1152/jn.00379.2006 ◽

2007 ◽

Vol 97 (1) ◽

pp. 604-617 ◽

Cited By ~ 22

Author(s):

Eliana M. Klier ◽

Hongying Wang ◽

J. Douglas Crawford

Keyword(s):

Coordinate System ◽

Degrees Of Freedom ◽

Three Dimensional ◽

Semicircular Canals ◽

Head Rotation ◽

Head Orientation ◽

Interstitial Nucleus Of Cajal ◽

The Gaze ◽

Behavioral Constraints ◽

The Right

Two central, related questions in motor control are 1) how the brain represents movement directions of various effectors like the eyes and head and 2) how it constrains their redundant degrees of freedom. The interstitial nucleus of Cajal (INC) integrates velocity commands from the gaze control system into position signals for three-dimensional eye and head posture. It has been shown that the right INC encodes clockwise (CW)-up and CW-down eye and head components, whereas the left INC encodes counterclockwise (CCW)-up and CCW-down components, similar to the sensitivity directions of the vertical semicircular canals. For the eyes, these canal-like coordinates align with Listing’s plane (a behavioral strategy limiting torsion about the gaze axis). By analogy, we predicted that the INC also encodes head orientation in canal-like coordinates, but instead, aligned with the coordinate axes for the Fick strategy (which constrains head torsion). Unilateral stimulation (50 μA, 300 Hz, 200 ms) evoked CW head rotations from the right INC and CCW rotations from the left INC, with variable vertical components. The observed axes of head rotation were consistent with a canal-like coordinate system. Moreover, as predicted, these axes remained fixed in the head, rotating with initial head orientation like the horizontal and torsional axes of a Fick coordinate system. This suggests that the head is ordinarily constrained to zero torsion in Fick coordinates by equally activating CW/CCW populations of neurons in the right/left INC. These data support a simple mechanism for controlling head orientation through the alignment of brain stem neural coordinates with natural behavioral constraints.

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A New Coordinate System for Magnetic Resonance Imaging of the Vestibular System

Frontiers in Neurology ◽

10.3389/fneur.2021.789887 ◽

2022 ◽

Vol 12 ◽

Author(s):

Weixing Liu ◽

Gui Chen ◽

Junyang Xie ◽

Tianhao Liang ◽

Chunyi Zhang ◽

...

Keyword(s):

Coordinate System ◽

Vestibular System ◽

Semicircular Canal ◽

Internal Auditory Canal ◽

Semicircular Canals ◽

Image Data ◽

Mean Values ◽

Medical Software ◽

Anterior Semicircular Canal ◽

Imaging Plane

Objectives: To develop and evaluate a new coordinate system for MRI of the vestibular system.Methods: In this study, 53 internal auditory canal MRI and 78 temporal bone CT datasets were analyzed. Mimics Medical software version 21.0 was used to visualize and three-dimensionally reconstruct the image data. We established a new coordinate system, named W–X, based on the center of the bilateral eyeballs and vertex of the bilateral superior semicircular canals. Using the W–X coordinate system and Reid's coordinate system, we measured the orientations of the planes of the anterior semicircular canal (ASCC), the lateral semicircular canal (LSCC), and the posterior semicircular canal (PSCC).Results: No significant differences between the angles measured using CT and MRI were found for any of the semicircular canal planes (p > 0.05). No statistical differences were found between the angles measured using Reid's coordinate system (CT) and the W–X coordinate system (MRI). The mean values of ∠ASCC & LSCC, ∠ASCC & PSCC, and ∠LSCC & PSCC were 84.67 ± 5.76, 94.21 ± 3.81, and 91.79 ± 5.22 degrees, respectively. The angle between the LSCC plane and the horizontal imaging plane was 15.64 ± 3.92 degrees, and the angle between the PSCC plane and the sagittal imaging plane was 48.79 ± 4.46 degrees.Conclusion: A new W–X coordinate system was developed for MRI studies of the vestibular system and can be used to measure the orientations of the semicircular canals.

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Mathematical Model of Human Semicircular Canal Spatial Attitude

10.21203/rs.3.rs-146523/v1 ◽

2021 ◽

Author(s):

Shu-zhi Wu ◽

Ping Lin ◽

Yan-yan Zheng ◽

Yi-fei Zhou ◽

Xiao-kai Yang

Keyword(s):

Mathematical Model ◽

Coordinate System ◽

Semicircular Canal ◽

Average Method ◽

Vestibular Function ◽

Semicircular Canals ◽

Normal Vector ◽

Spatial Coordinate ◽

Average Value ◽

Plane Normal

Abstract Located deep in the temporal bone, the semicircular canal is a subtle structure that requires a spatial coordinate system for measurement and observation. In this study,Fifty-five semicircular canal and eyeball models were obtained by segmentation of MRI data. The spatial coordinate system was established by taking the top of the common crus and the bottom of eyeball as the horizontal plane. Firstly, the plane equation is calculated according to the centerline of the semicircular canals. Then, according to the parameters of the plane equation, the plane normal vectors are obtained. Finally, the average unit normal vector of each semicircular canal plane can be obtained by calculating the average value of the vectors. It is more intuitive and accurate to calculate the average normal vector of semicircular canal plane with the vector average method, which is different from the angular average method in different degrees. The mathematical model of semicircular canal spatial attitude established in this study is more reliable, which can guide the vestibular function examination, and also help guide the diagnosis and treatment of BPPV.

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Reference Coordinate System Requirements for Geophysics

International Astronomical Union Colloquium ◽

10.1017/s0252921100050946 ◽

1975 ◽

Vol 26 ◽

pp. 87-92

Author(s):

P. L. Bender

Keyword(s):

Coordinate System ◽

Polar Motion ◽

Main Part ◽

Measurement Techniques ◽

Reference Points ◽

Angular Motion ◽

Coordinate Systems ◽

Axis Of Rotation ◽

The Earth ◽

Fixed System

AbstractFive important geodynamical quantities which are closely linked are: 1) motions of points on the Earth’s surface; 2)polar motion; 3) changes in UT1-UTC; 4) nutation; and 5) motion of the geocenter. For each of these we expect to achieve measurements in the near future which have an accuracy of 1 to 3 cm or 0.3 to 1 milliarcsec.From a metrological point of view, one can say simply: “Measure each quantity against whichever coordinate system you can make the most accurate measurements with respect to”. I believe that this statement should serve as a guiding principle for the recommendations of the colloquium. However, it also is important that the coordinate systems help to provide a clear separation between the different phenomena of interest, and correspond closely to the conceptual definitions in terms of which geophysicists think about the phenomena.In any discussion of angular motion in space, both a “body-fixed” system and a “space-fixed” system are used. Some relevant types of coordinate systems, reference directions, or reference points which have been considered are: 1) celestial systems based on optical star catalogs, distant galaxies, radio source catalogs, or the Moon and inner planets; 2) the Earth’s axis of rotation, which defines a line through the Earth as well as a celestial reference direction; 3) the geocenter; and 4) “quasi-Earth-fixed” coordinate systems.When a geophysicists discusses UT1 and polar motion, he usually is thinking of the angular motion of the main part of the mantle with respect to an inertial frame and to the direction of the spin axis. Since the velocities of relative motion in most of the mantle are expectd to be extremely small, even if “substantial” deep convection is occurring, the conceptual “quasi-Earth-fixed” reference frame seems well defined. Methods for realizing a close approximation to this frame fortunately exist. Hopefully, this colloquium will recommend procedures for establishing and maintaining such a system for use in geodynamics. Motion of points on the Earth’s surface and of the geocenter can be measured against such a system with the full accuracy of the new techniques.The situation with respect to celestial reference frames is different. The various measurement techniques give changes in the orientation of the Earth, relative to different systems, so that we would like to know the relative motions of the systems in order to compare the results. However, there does not appear to be a need for defining any new system. Subjective figures of merit for the various system dependon both the accuracy with which measurements can be made against them and the degree to which they can be related to inertial systems.The main coordinate system requirement related to the 5 geodynamic quantities discussed in this talk is thus for the establishment and maintenance of a “quasi-Earth-fixed” coordinate system which closely approximates the motion of the main part of the mantle. Changes in the orientation of this system with respect to the various celestial systems can be determined by both the new and the conventional techniques, provided that some knowledge of changes in the local vertical is available. Changes in the axis of rotation and in the geocenter with respect to this system also can be obtained, as well as measurements of nutation.

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2.2. Working Group 2: Conceptual Definitions of Reference Coordinate Systems for Earth Dynamics

International Astronomical Union Colloquium ◽

10.1017/s0252921100050867 ◽

1975 ◽

Vol 26 ◽

pp. 21-26

Keyword(s):

Coordinate System ◽

Working Group ◽

General Character ◽

Coordinate Systems ◽

Reference Coordinate System ◽

Group 2 ◽

Definition Of ◽

Earth Dynamics

An ideal definition of a reference coordinate system should meet the following general requirements:1. It should be as conceptually simple as possible, so its philosophy is well understood by the users.2. It should imply as few physical assumptions as possible. Wherever they are necessary, such assumptions should be of a very general character and, in particular, they should not be dependent upon astronomical and geophysical detailed theories.3. It should suggest a materialization that is dynamically stable and is accessible to observations with the required accuracy.

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The Scanning Electron Microscopic Observation of the Vestibular Sensory Epithelia

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100062105 ◽

1969 ◽

Vol 27 ◽

pp. 40-41

Author(s):

D.J. Lim ◽

W.C. Lane

Keyword(s):

Semicircular Canals ◽

Electron Microscopic Observation ◽

Gravitational Acceleration ◽

Electron Microscopic ◽

Sensory Epithelia ◽

Scanning Electron Microscopic ◽

Vestibular Sensory Epithelia ◽

And Function ◽

Sand Piles ◽

Active Investigation

The morphology and function of the vestibular sensory organs has been extensively studied during the last decade with the advent of electron microscopy and electrophysiology. The opening of the space age also accelerated active investigation in this area, since this organ is responsible for the sensation of balance and of linear, angular and gravitational acceleration.The vestibular sense organs are formed by the saccule, utricle and three ampullae of the semicircular canals. The maculae (sacculi and utriculi) have otolithic membranes on the top of the sensory epithelia. The otolithic membrane is formed by a layer of thick gelatin and sand-piles of calcium carbonate crystals (Fig.l).

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