scholarly journals Utricular afferents: morphology of peripheral terminals

2015 ◽  
Vol 113 (7) ◽  
pp. 2420-2433 ◽  
Author(s):  
J. A. Huwe ◽  
G. J. Logan ◽  
B. Williams ◽  
M. H. Rowe ◽  
E. H. Peterson
Keyword(s):  
Head Movement ◽  
Calcium Binding ◽  
Three Dimensional ◽  
Small Diameter ◽  
Head Movements ◽  
Hair Bundle ◽  
Movement Direction ◽  
Head Orientation ◽  
Functional Roles ◽  
Bundle Structure

The utricle provides critical information about spatiotemporal properties of head movement. It comprises multiple subdivisions whose functional roles are poorly understood. We previously identified four subdivisions in turtle utricle, based on hair bundle structure and mechanics, otoconial membrane structure and hair bundle coupling, and immunoreactivity to calcium-binding proteins. Here we ask whether these macular subdivisions are innervated by distinctive populations of afferents to help us understand the role each subdivision plays in signaling head movements. We quantified the morphology of 173 afferents and identified six afferent classes, which differ in structure and macular locus. Calyceal and dimorphic afferents innervate one striolar band. Bouton afferents innervate a second striolar band; they have elongated terminals and the thickest processes and axons of all bouton units. Bouton afferents in lateral (LES) and medial (MES) extrastriolae have small-diameter axons but differ in collecting area, bouton number, and hair cell contacts (LES >> MES). A fourth, distinctive population of bouton afferents supplies the juxtastriola. These results, combined with our earlier findings on utricular hair cells and the otoconial membrane, suggest the hypotheses that MES and calyceal afferents encode head movement direction with high spatial resolution and that MES afferents are well suited to signal three-dimensional head orientation and striolar afferents to signal head movement onset.

Cross-validated models of the relationships between neck muscle electromyography and three-dimensional head kinematics during gaze behavior

2012 ◽  
Vol 107 (2) ◽  
pp. 573-590 ◽  
Author(s):  
Farshad Farshadmanesh ◽  
Patrick Byrne ◽  
Gerald P. Keith ◽  
Hongying Wang ◽  
Brian D. Corneil ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Head Movements ◽  
Polynomial Model ◽  
Emg Activity ◽  
Head Orientation ◽  
Gaze Behavior ◽  
Data Set ◽  
Head Kinematics ◽  
Musculoskeletal Anatomy ◽  
Horizontal Head

The object of this study was to model the relationship between neck electromyography (EMG) and three-dimensional (3-D) head kinematics during gaze behavior. In two monkeys, we recorded 3-D gaze, head orientation, and bilateral EMG activity in the sternocleidomastoid, splenius capitis, complexus, biventer cervicis, rectus capitis posterior major, and occipital capitis inferior muscles. Head-unrestrained animals fixated and made gaze saccades between targets within a 60° × 60° grid. We performed a stepwise regression in which polynomial model terms were retained/rejected based on their tendency to increase/decrease a cross-validation-based measure of model generalizability. This revealed several results that could not have been predicted from knowledge of musculoskeletal anatomy. During head holding, EMG activity in most muscles was related to horizontal head orientation, whereas fewer muscles correlated to vertical head orientation and none to small random variations in head torsion. A fourth-order polynomial model, with horizontal head orientation as the only independent variable, generalized nearly as well as higher order models. For head movements, we added time-varying linear and nonlinear perturbations in velocity and acceleration to the previously derived static (head holding) models. The static models still explained most of the EMG variance, but the additional motion terms, which included horizontal, vertical, and torsional contributions, significantly improved the results. Several coordinate systems were used for both static and dynamic analyses, with Fick coordinates showing a marginal (nonsignificant) advantage. Thus, during gaze fixations, recruitment within the neck muscles from which we recorded contributed primarily to position-dependent horizontal orientation terms in our data set, with more complex multidimensional contributions emerging during the head movements that accompany gaze shifts. These are crucial components of the late neuromuscular transformations in a complete model of 3-D head-neck system and should help constrain the study of premotor signals for head control during gaze behaviors.

Effect of radius versus rotation speed in artificial gravity

2008 ◽  
Vol 17 (5-6) ◽  
pp. 333-346
Author(s):  
Jan E. Holly
Keyword(s):  
Motion Sickness ◽  
Head Movement ◽  
Rotation Speed ◽  
Head Movements ◽  
Three Dimensions ◽  
Artificial Gravity ◽  
Whole Body ◽  
Movement Direction ◽  
Least Disturbance ◽  
Significant Disturbance

Artificial gravity by centrifugation can lead to perceptual disturbances in the form of motion sickness and/or misperception of motion during head movements, but the degree of perceptual disturbance during centrifugation in 0-g has not been thoroughly investigated. It is known that during whole-body on-axis yaw rotation in 0-g, head movements in pitch and roll cause very little disturbance, despite significant disturbance in 1-g. Therefore, 1-g experimental results do not apply directly to 0-g without further analysis. A modeling approach was used here to predict disorienting effects in 0-g and 1-g environments, with different rotation speeds, centrifuge radii, and directions of head movement. The results were based upon investigation of the stimulus itself, in the form of angular and linear accelerations, and their consequences due to linear-angular interactions in three dimensions. The results explain known differences in 0-g and 1-g, for head turns toward and away from the direction of motion, and for head movements on- and off-axis. Additional predictions include an increase in perceptual disturbance with the magnitude of the gravito-inertial acceleration (GIA), therefore an increase off-axis, but a decrease in 0-g. Also predicted is that head-movement direction makes a difference, with rotation outward relative to the centrifuge axis causing the least disturbance.

scholarly journals Steady-state stiffness of utricular hair cells depends on macular location and hair bundle structure

2011 ◽  
Vol 106 (6) ◽  
pp. 2950-2963 ◽  
Author(s):  
Corrie Spoon ◽  
W. J. Moravec ◽  
M. H. Rowe ◽  
J. W. Grant ◽  
E. H. Peterson
Keyword(s):  
Steady State ◽  
Hair Cells ◽  
Head Movement ◽  
Time Course ◽  
Hair Bundle ◽  
Type I ◽  
Response Dynamics ◽  
Functional Interpretation ◽  
Hair Bundles ◽  
Bundle Structure

Spatial and temporal properties of head movement are encoded by vestibular hair cells in the inner ear. One of the most striking features of these receptors is the orderly structural variation in their mechanoreceptive hair bundles, but the functional significance of this diversity is poorly understood. We tested the hypothesis that hair bundle structure is a significant contributor to hair bundle mechanics by comparing structure and steady-state stiffness of 73 hair bundles at varying locations on the utricular macula. Our first major finding is that stiffness of utricular hair bundles varies systematically with macular locus. Stiffness values are highest in the striola, near the line of hair bundle polarity reversal, and decline exponentially toward the medial extrastriola. Striolar bundles are significantly more stiff than those in medial (median: 8.9 μN/m) and lateral (2.0 μN/m) extrastriolae. Within the striola, bundle stiffness is greatest in zone 2 (106.4 μN/m), a band of type II hair cells, and significantly less in zone 3 (30.6 μN/m), which contains the only type I hair cells in the macula. Bathing bundles in media that break interciliary links produced changes in bundle stiffness with predictable time course and magnitude, suggesting that links were intact in our standard media and contributed normally to bundle stiffness during measurements. Our second major finding is that bundle structure is a significant predictor of steady-state stiffness: the heights of kinocilia and the tallest stereocilia are the most important determinants of bundle stiffness. Our results suggest 1) a functional interpretation of bundle height variability in vertebrate vestibular organs, 2) a role for the striola in detecting onset of head movement, and 3) the hypothesis that differences in bundle stiffness contribute to diversity in afferent response dynamics.

Rostral Fastigial Nucleus Activity in the Alert Monkey During Three-Dimensional Passive Head Movements

1997 ◽  
Vol 77 (3) ◽  
pp. 1432-1446 ◽  
Author(s):  
C. Siebold ◽  
L. Glonti ◽  
S. Glasauer ◽  
U. Büttner
Keyword(s):  
Phase Relation ◽  
Response Pattern ◽  
Three Dimensional ◽  
Head Movements ◽  
Fastigial Nucleus ◽  
Head Orientation ◽  
Alert Monkey ◽  
Horizontal Canal ◽  
Response Vector ◽  
Dynamic Stimulation

Siebold, C., L. Glonti, S. Glasauer, and U. Büttner. Rostral fastigial nucleus activity in the alert monkey during three-dimensional passive head movements. J. Neurophysiol. 77: 1432–1446, 1997. The fastigial nucleus (FN) receives vestibular information predominantly from Purkinje cells of the vermis. FN in the monkey can be divided in a rostral part, related to spinal mechanisms, and a caudal part with oculomotor functions. To understand the role of FN during movements in space, single-unit activity in alert monkeys was recorded during passive three-dimensional head movements from rostral FN. Seated monkeys were rotated sinusoidally around a horizontal earth-fixed axis (vertical stimulation) at different orientations 15° apart (including roll, pitch, vertical canal plane and intermediate planes). In addition, sinusoidal rotations around an earth-vertical axis (yaw stimulus) included different roll and pitch positions (±10°, ±20°). The latter positions were also used for static stimulation. One hundred fifty-eight neurons in two monkeys were modulated during the sinusoidal vertical search stimulation. The vast majority showed a uniform response pattern: a maximum at a specific head orientation (response vector orientation) and a null response 90° apart. Detailed analysis was obtained from 111 neurons. On the basis of their phase relation during dynamic stimulation and their response to static tilt, these neurons were classified as vertical semicircular canal related ( n = 79, 71.2%) or otolith related ( n = 25; 22.5%). Only seven neurons did not follow the usual response pattern and were classified as complex neurons. For the vertical canal-related neurons ( n = 79) all eight major response vector orientations (ipsilateral or contralateral anterior canal, posterior canal, roll, and nose-down and nose-up pitch) were found in FN on one side. Neurons with ipsilateral orientations were more numerous and on average more sensitive than those with contralateral orientations. Twenty-eight percent of the vertical canal-related neurons also responded to horizontal canal stimulation. None of the vertical canal-related neurons responded to static tilt. Otolith-related neurons ( n = 25) had a phase relation close to head position and were considerably less numerous than canal-related neurons. Except for pitch, all other response vector orientations were found. Seventy percent of these neurons responding during dynamic stimulation also responded during static tilt. The sensitivity during dynamic stimulation was always higher than during static stimulation. Sixty-one percent of the otolith-related neurons responded also to horizontal canal stimulation. These results show that in FN, robust vestibular signals are abundant. Canal-related responses are much more common than otolith-related responses. Although for many canal neurons the responses can be related to single canal planes, convergence between vertical canals but also with horizontal canals is common.

Role of pinnae and head movements in localizing pure tones 1The authors would like to thank Mr. Remi Humbert for implementing the experiment in Turbo Pascal and for his further assistance.

1999 ◽  
Vol 58 (3) ◽  
pp. 170-179 ◽  
Author(s):  
Barbara S. Muller ◽  
Pierre Bovet
Keyword(s):  
Sound Source ◽  
Head Movement ◽  
Movement Analysis ◽  
Head Movements ◽  
Sound Sources ◽  
Localization Accuracy ◽  
Sound Effects ◽  
Posterior Quadrant ◽  
Localization Performance ◽  
Pure Tones

Twelve blindfolded subjects localized two different pure tones, randomly played by eight sound sources in the horizontal plane. Either subjects could get information supplied by their pinnae (external ear) and their head movements or not. We found that pinnae, as well as head movements, had a marked influence on auditory localization performance with this type of sound. Effects of pinnae and head movements seemed to be additive; the absence of one or the other factor provoked the same loss of localization accuracy and even much the same error pattern. Head movement analysis showed that subjects turn their face towards the emitting sound source, except for sources exactly in the front or exactly in the rear, which are identified by turning the head to both sides. The head movement amplitude increased smoothly as the sound source moved from the anterior to the posterior quadrant.

scholarly journals Exosomal S100A4 derived from highly metastatic hepatocellular carcinoma cells promotes metastasis by activating STAT3

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Haoting Sun ◽  
Chaoqun Wang ◽  
Beiyuan Hu ◽  
Xiaomei Gao ◽  
Tiantian Zou ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cancer Progression ◽  
Calcium Binding ◽  
Tumor Metastasis ◽  
Metastatic Potential ◽  
Functional Roles ◽  
Stat3 Phosphorylation ◽  
Hcc Cells

AbstractIntercellular cross-talk plays important roles in cancer progression and metastasis. Yet how these cancer cells interact with each other is still largely unknown. Exosomes released by tumor cells have been proved to be effective cell-to-cell signal mediators. We explored the functional roles of exosomes in metastasis and the potential prognostic values for hepatocellular carcinoma (HCC). Exosomes were extracted from HCC cells of different metastatic potentials. The metastatic effects of exosomes derived from highly metastatic HCC cells (HMH) were evaluated both in vitro and in vivo. Exosomal proteins were identified with iTRAQ mass spectrum and verified in cell lines, xenograft tumor samples, and functional analyses. Exosomes released by HMH significantly enhanced the in vitro invasion and in vivo metastasis of low metastatic HCC cells (LMH). S100 calcium-binding protein A4 (S100A4) was identified as a functional factor in exosomes derived from HMH. S100A4rich exosomes significantly promoted tumor metastasis both in vitro and in vivo compared with S100A4low exosomes or controls. Moreover, exosomal S100A4 could induce expression of osteopontin (OPN), along with other tumor metastasis/stemness-related genes. Exosomal S100A4 activated OPN transcription via STAT3 phosphorylation. HCC patients with high exosomal S100A4 in plasma also had a poorer prognosis. In conclusion, exosomes from HMH could promote the metastatic potential of LMH, and exosomal S100A4 is a key enhancer for HCC metastasis, activating STAT3 phosphorylation and up-regulating OPN expression. This suggested exosomal S100A4 to be a novel prognostic marker and therapeutic target for HCC metastasis.

Three Dimensional Video Imaging for Endoscopic Sinus Surgery and Diagnosis

1995 ◽  
Vol 9 (4) ◽  
pp. 197-202 ◽  
Author(s):  
Anthony J. Reino ◽  
William Lawson ◽  
Baxter J. Garcia ◽  
Robert J. Greenstein
Keyword(s):  
Endoscopic Sinus Surgery ◽  
Three Dimensional ◽  
Small Diameter ◽  
Image Distortion ◽  
Sinus Surgery ◽  
Depth Of Field ◽  
Visual Fatigue ◽  
Video Imaging ◽  
Video Cameras ◽  
Technological Advances

Technological advances in video imaging over the last decade have resulted in remarkable additions to the armamentarium of instrumentation for the otolaryngologist. The use of video cameras and computer generated imaging in the operating room and office is invaluable for documentation and teaching purposes. Despite the obvious advantages of these systems, problems are evident, the most serious of which include image distortion and inability to judge depth of field. For more than 6 decades 3D imaging has been neither technically nor commercially successful. Reasons include alignment difficulties and image distortion. The result is “visual fatigue,” usually in about 15 minutes. At its extreme, this may be characterized by headache, nausea, and even vomiting. In this study, we employed the first 3D video imager to electronically manipulate a single video source to produce 3D images; therefore, neither alignment nor image distortions were produced. Of interest to the clinical surgeon, “visual fatigue” does not seem to occur; however, with prolonged procedures (greater than 2 hours) there exists the potential for physical intolerance for some individuals. This is the first unit that is compatible with any rigid or flexible videoendoscopic system and the small diameter endoscopes available for endoscopic sinus surgery. Moreover, prerecorded 2D tapes may be viewed in 3D on an existing VCR. The 3D image seems to provide enhanced anatomic awareness with less image distortion. We have found this system to be optically superior to the 2D video imagers currently available.

scholarly journals Neural Basis of Visually Guided Head Movements Studied With fMRI

2003 ◽  
Vol 89 (5) ◽  
pp. 2516-2527 ◽  
Author(s):  
Laurent Petit ◽  
Michael S. Beauchamp
Keyword(s):  
Eye Movements ◽  
Head Movement ◽  
Brain Activity ◽  
Posterior Part ◽  
Vestibular Stimulation ◽  
Head Movements ◽  
Oculomotor Control ◽  
Imaging Studies ◽  
Neural Basis ◽  
Temporoparietal Junction

We used event-related fMRI to measure brain activity while subjects performed saccadic eye, head, and gaze movements to visually presented targets. Two distinct patterns of response were observed. One set of areas was equally active during eye, head, and gaze movements and consisted of the superior and inferior subdivisions of the frontal eye fields, the supplementary eye field, the intraparietal sulcus, the precuneus, area MT in the lateral occipital sulcus and subcortically in basal ganglia, thalamus, and the superior colliculus. These areas have been previously observed in functional imaging studies of human eye movements, suggesting that a common set of brain areas subserves both oculomotor and head movement control in humans, consistent with data from single-unit recording and microstimulation studies in nonhuman primates that have described overlapping eye- and head-movement representations in oculomotor control areas. A second set of areas was active during head and gaze movements but not during eye movements. This set of areas included the posterior part of the planum temporale and the cortex at the temporoparietal junction, known as the parieto-insular vestibular cortex (PIVC). Activity in PIVC has been observed during imaging studies of invasive vestibular stimulation, and we confirm its role in processing the vestibular cues accompanying natural head movements. Our findings demonstrate that fMRI can be used to study the neural basis of head movements and show that areas that control eye movements also control head movements. In addition, we provide the first evidence for brain activity associated with vestibular input produced by natural head movements as opposed to invasive caloric or galvanic vestibular stimulation.

scholarly journals Development of a Drawing Application for Communication Support during Endoscopic Surgery and its Evaluation Using Steering Law

2021 ◽  
Vol 11 (10) ◽  
pp. 4505
Author(s):  
Takafumi Asao ◽  
Takeru Kobayashi ◽  
Kentaro Kotani ◽  
Satoshi Suzuki ◽  
Kazutaka Obama ◽  
...  
Keyword(s):  
Endoscopic Surgery ◽  
Head Movement ◽  
Movement Time ◽  
Collaborative Work ◽  
Subjective Evaluation ◽  
Line Drawing ◽  
Head Movements ◽  
Coefficient Of Determination ◽  
Communication Support ◽  
Steering Law

The purpose of this study is to construct a hands-free endoscopic surgical communication support system that can draw lines in space corresponding to head movements using AR technology and evaluate the applicability of the drawing motion by the head movement to the steering law, one of the HCI models, for the potential use during endoscopic surgery. In the experiment, the participants manipulated the cursor by using head movements through the pathway and movement time (MT); the number of errors and subjective evaluation of the difficulty of the task was obtained. The results showed that the head-movement-based line drawing manipulation was significantly affected by the tracking direction and by the task difficulty, shown as the Index of Difficulty (ID). There was high linearity between ID and MT, with a coefficient of determination R² of 0.9991. The Index of Performance was higher in the horizontal and vertical directions compared to diagonal directions. Although the weight and biocompatibility of the AR glasses must be overcome to make the current prototype a viable tool for supporting communication in the operating room environment, the prototype has the potential to promote the development of a computer-supported collaborative work environment for endoscopic surgery purposes.

Sign in / Sign up

Export Citation Format

Share Document