Response of central vestibular neurons to horizontal linear acceleration in the rat

1980 ◽  
Vol 385 (2) ◽  
pp. 123-129 ◽  
Author(s):  
J. Lannou ◽  
L. Cazin ◽  
K. -F. Hamann
Keyword(s):  
Linear Acceleration ◽  
Vestibular Neurons

Patterns of Canal and Otolith Afferent Input Convergence in Frog Second-Order Vestibular Neurons

2002 ◽  
Vol 88 (5) ◽  
pp. 2287-2301 ◽  
Author(s):  
H. Straka ◽  
S. Holler ◽  
F. Goto
Keyword(s):  
Semicircular Canal ◽  
Linear Acceleration ◽  
Afferent Input ◽  
Second Order ◽  
Head Movements ◽  
Otolith Organs ◽  
Otolith Organ ◽  
Horizontal Canal ◽  
Vestibular Neurons ◽  
Saccular Nerve

Second-order vestibular neurons (2°VN) were identified in the isolated frog brain by the presence of monosynaptic excitatory postsynaptic potentials (EPSPs) after separate electrical stimulation of individual vestibular nerve branches. Combinations of one macular and the three semicircular canal nerve branches or combinations of two macular nerve branches were stimulated separately in different sets of experiments. Monosynaptic EPSPs evoked from the utricle or from the lagena converged with monosynaptic EPSPs from one of the three semicircular canal organs in ∼30% of 2°VN. Utricular afferent signals converged predominantly with horizontal canal afferent signals (74%), and lagenar afferent signals converged with anterior vertical (63%) or posterior vertical (37%) but not with horizontal canal afferent signals. This convergence pattern correlates with the coactivation of particular combinations of canal and otolith organs during natural head movements. A convergence of afferent saccular and canal signals was restricted to very few 2°VN (3%). In contrast to the considerable number of 2°VN that received an afferent input from the utricle or the lagena as well as from one of the three canal nerves (∼30%), smaller numbers of 2°VN (14% of each type of 2°otolith or 2°canal neuron) received an afferent input from only one particular otolith organ or from only one particular semicircular canal organ. Even fewer 2°VN received an afferent input from more than one semicircular canal or from more than one otolith nerve (∼7% each). Among 2°VN with afferent inputs from more than one otolith nerve, an afferent saccular nerve input was particularly rare (4–5%). The restricted convergence of afferent saccular inputs with other afferent otolith or canal inputs as well as the termination pattern of saccular afferent fibers are compatible with a substrate vibration sensitivity of this otolith organ in frog. The ascending and/or descending projections of identified 2°VN were determined by the presence of antidromic spikes. 2°VN mediating afferent utricular and/or semicircular canal nerve signals had ascending and/or descending axons. 2°VN mediating afferent lagenar or saccular nerve signals had descending but no ascending axons. The latter result is consistent with the absence of short-latency macular signals on extraocular motoneurons during vertical linear acceleration. Comparison of data from frog and cat demonstrated the presence of a similar organization pattern of maculo- and canal-ocular reflexes in both species.

Excitatory and Inhibitory Inputs From Saccular Afferents to Single Vestibular Neurons in the Cat

1997 ◽  
Vol 78 (4) ◽  
pp. 2186-2192 ◽  
Author(s):  
Y. Uchino ◽  
H. Sato ◽  
H. Suwa
Keyword(s):  
Hair Cells ◽  
Semicircular Canal ◽  
Response Pattern ◽  
Linear Acceleration ◽  
High Sensitivity ◽  
Vestibular Neurons ◽  
Dorsal Edge ◽  
Stimulus Current ◽  
Saccular Nerve ◽  
Stimulation Of

Uchino, Y., H. Sato, and H. Suwa. Excitatory and inhibitory inputs from saccular afferents to single vestibular neurons in the cat. J. Neurophysiol. 78: 2186–2192, 1997. Connections from saccular afferents to vestibular neurons were studied by means of intracellular recordings of excitatory (E) and inhibitory (I) postsynaptic potentials (PSPs) in vestibular neurons after focal stimulation of the saccular macula in decerebrated cats. Focal stimulation was given to the saccular macula in two ways, in which the polarity of stimulus current via a pair of electrodes was changed. In group A, one of the electrodes was inserted into the ventral and the other into the dorsal edge of the saccular macula. The focal stimulation was across the striola so that the reversal of morphological polarization in hair cells was bridged by the pulse stimulus. In 22/36 vestibular neurons tested, the stimulation of the saccular macula evoked monosynaptic (≤1.2 ms) EPSPs, including EPSP-IPSP sequences, with one polarity of stimulation, and disynaptic (≥1.5 ms) IPSPs when the polarity of the stimulus current was changed. In 14/36 neurons, the response pattern was the same regardless of the stimulus polarity; EPSPs (12/36) or IPSPs (2/36). In group B, a pair of electrodes was inserted into the dorsal edge of the saccular macula, so that the striola was not bridged by the current stimulus. In all of the vestibular neurons tested, the response pattern was always the same regardless of the polarity: mono- (22/31) and disynaptic (3/31) EPSPs or disynaptic IPSPs (6/31). In addition, the saccular nerve was stimulated after removing the macula in some cats ( group C). The stimulation of the saccular nerve evoked EPSPs in 62 vestibular neurons (including EPSP-IPSP sequences in 31 neurons) and IPSPs in 19 vestibular neurons. Convergence between the saccular nerve and other vestibular nerves was studied by the intracellular recording of PSPs. Fifty-six percent (18/32) of the saccular-activated neurons had excitatory and/or inhibitory potentials evoked after stimulation of the utricular nerve and the horizontal and anterior semicircular canal nerves, and 44% (19/43) of the neurons received inputs from the posterior semicircular canal nerve. The results support the hypothesis that saccular afferents from one population of hair cells activate vestibular neurons monosynaptically and that afferents from another population of hair cells located on the opposite side of the striola appear to project to the same vestibular neurons disynaptically via inhibitory interneurons. Neural circuits from saccular afferents to vestibular neurons, which we term cross-striolar inhibition, thus may provide a mechanism for increasing the sensitivity to vertical linear acceleration. The circuit described is provided not only with high sensitivity but also with input noise-resistant characteristics.

Head Impact Biomechanics in Youth Flag Football: A Prospective Cohort Study

2021 ◽  
pp. 036354652110266
Author(s):  
Landon B. Lempke ◽  
Rachel S. Johnson ◽  
Rachel K. Le ◽  
Melissa N. Anderson ◽  
Julianne D. Schmidt ◽  
...  
Keyword(s):  
Mixed Model ◽  
Linear Acceleration ◽  
Cross Sectional Study ◽  
Head Impact ◽  
Rotational Acceleration ◽  
Event Type ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Head Impact Biomechanics ◽  
Impact Biomechanics

Background: Youth flag football participation has rapidly grown and is a potentially safer alternative to tackle football. However, limited research has quantitatively assessed youth flag football head impact biomechanics. Purpose: To describe head impact biomechanics outcomes in youth flag football and explore factors associated with head impact magnitudes. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We monitored 52 player-seasons among 48 male flag football players (mean ± SD; age, 9.4 ± 1.1 years; height, 138.6 ± 9.5 cm; mass, 34.7 ± 9.2 kg) across 3 seasons using head impact sensors during practices and games. Sensors recorded head impact frequencies, peak linear ( g) and rotational (rad/s2) acceleration, and estimated impact location. Impact rates (IRs) were calculated as 1 impact per 10 player-exposures; IR ratios (IRRs) were used to compare season, event type, and age group IRs; and 95% CIs were calculated for IRs and IRRs. Weekly and seasonal cumulative head impact frequencies and magnitudes were calculated. Mixed-model regression models examined the association between player characteristics, event type, and seasons and peak linear and rotational accelerations. Results: A total of 429 head impacts from 604 exposures occurred across the study period (IR, 7.10; 95% CI, 4.81-10.50). Weekly and seasonal cumulative median head impact frequencies were 1.00 (range, 0-2.63) and 7.50 (range, 0-21.00), respectively. The most frequent estimated head impact locations were the skull base (n = 96; 22.4%), top of the head (n = 74; 17.2%), and back of the head (n = 66; 15.4%). The combined event type IRs differed among the 3 seasons (IRR range, 1.45-2.68). Games produced greater IRs (IRR, 1.24; 95% CI, 1.01-1.53) and peak linear acceleration (mean difference, 5.69 g; P = .008) than did practices. Older players demonstrated greater combined event–type IRs (IRR, 1.46; 95% CI, 1.12-1.90) and increased head impact magnitudes than did younger players, with every 1-year age increase associated with a 3.78 g and 602.81-rad/s2 increase in peak linear and rotational acceleration magnitude, respectively ( P≤ .005). Conclusion: Head IRs and magnitudes varied across seasons, thus highlighting multiple season and cohort data are valuable when providing estimates. Head IRs were relatively low across seasons, while linear and rotational acceleration magnitudes were relatively high.

scholarly journals Development of a new method for assessing otolith function in mice using three-dimensional binocular analysis of the otolith-ocular reflex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shotaro Harada ◽  
Takao Imai ◽  
Yasumitsu Takimoto ◽  
Yumi Ohta ◽  
Takashi Sato ◽  
...  
Keyword(s):  
Eye Movement ◽  
Three Dimensional ◽  
Vertical Component ◽  
Inertial Force ◽  
Linear Acceleration ◽  
The Body ◽  
Body Axis ◽  
Gravitational Acceleration ◽  
Ocular Reflex ◽  
Translational Movement

AbstractIn the interaural direction, translational linear acceleration is loaded during lateral translational movement and gravitational acceleration is loaded during lateral tilting movement. These two types of acceleration induce eye movements via two kinds of otolith-ocular reflexes to compensate for movement and maintain clear vision: horizontal eye movement during translational movement, and torsional eye movement (torsion) during tilting movement. Although the two types of acceleration cannot be discriminated, the two otolith-ocular reflexes can distinguish them effectively. In the current study, we tested whether lateral-eyed mice exhibit both of these otolith-ocular reflexes. In addition, we propose a new index for assessing the otolith-ocular reflex in mice. During lateral translational movement, mice did not show appropriate horizontal eye movement, but exhibited unnecessary vertical torsion-like eye movement that compensated for the angle between the body axis and gravito-inertial acceleration (GIA; i.e., the sum of gravity and inertial force due to movement) by interpreting GIA as gravity. Using the new index (amplitude of vertical component of eye movement)/(angle between body axis and GIA), the mouse otolith-ocular reflex can be assessed without determining whether the otolith-ocular reflex is induced during translational movement or during tilting movement.

scholarly journals Football concussion case series using biomechanical and video analysis

Neurology ◽  
2018 ◽  
Vol 91 (23 Supplement 1) ◽  
pp. S2.2-S2
Author(s):  
Mirellie Kelley ◽  
Jillian Urban ◽  
Derek Jones ◽  
Alexander Powers ◽  
Christopher T. Whitlow ◽  
...  
Keyword(s):  
Video Analysis ◽  
Case Series ◽  
Linear Acceleration ◽  
The United States ◽  
Head Impact ◽  
Rotational Acceleration ◽  
Impact Location ◽  
Injury Mechanisms ◽  
The Mean ◽  
Impact Data

Approximately 1.1–1.9 million sport-related concussions among athletes ≤18 years of age occur annually in the United States, but there is limited understanding of the biomechanics and injury mechanisms associated with concussions among lower level football athletes. Therefore, the objective of this study was to combine biomechanical head impact data with video analysis to characterize youth and HS football concussion injury mechanisms. Head impact data were collected from athletes participating on 22 youth and 6 HS football teams between 2012 and 2017. Video was recorded, and head impact data were collected during all practices and games by instrumenting players with the Head Impact Telemetry (HIT) System. For each clinically diagnosed concussion, a video abstraction form was completed, which included questions concerning the context in which the injury occurred. Linear acceleration, rotational acceleration, and impact location were used to characterize the concussive event and each injured athlete's head impact exposure on the day of the concussion. A total of 9 (5 HS and 4 youth) concussions with biomechanics and video of the event were included in this study. The mean [range] linear and rotational acceleration of the concussive impacts were 62.9 [29.3–118.4] g and 3,056.7 [1,046.8–6,954.6] rad/s2, respectively. Concussive impacts were the highest magnitude impacts for 6 players and in the top quartile of impacts for 3 players on the day of injury. Concussions occurred in both practices (N = 4) and games (N = 5). The most common injury contact surface was helmet-to-helmet (N = 5), followed by helmet-to-ground (N = 3) and helmet-to-body (N = 1). All injuries occurred during player-to-player contact scenarios, including tackling (N = 4), blocking (N = 4), and collision with other players (N = 1). The biomechanics and injury mechanisms of concussions varied among athletes in our study; however, concussive impacts were among the highest severity for each player and all concussions occurred as a result of player-to-player contact.

Autoradiographic measurement of tritiated agmatine as an indicator of physiologic activity inHermissenda visual and vestibular neurons

1986 ◽  
Vol 15 (5) ◽  
pp. 629-643 ◽  
Author(s):  
Alan M. Kuzirian ◽  
Edgar Meyhöfer ◽  
Lena Hill ◽  
Joseph T. Neary ◽  
Daniel L. Alkon
Keyword(s):  
Vestibular Neurons ◽  
Physiologic Activity

Velocity control algorithm in glass polishing based on the cubic NURBS curve

2017 ◽  
Vol 232 (4) ◽  
pp. 685-696 ◽  
Author(s):  
Junzhao Han ◽  
Wenhua Chen
Keyword(s):  
Control Algorithm ◽  
Linear Acceleration ◽  
Control Points ◽  
Velocity Control ◽  
Polishing Process ◽  
Nurbs Curve ◽  
Weighting Factors ◽  
Final Velocity ◽  
Contact Points ◽  
Glass Polishing

To limit velocity fluctuations and to achieve a controllable jerk value in a glass polishing process, a new velocity control algorithm is proposed based on nonuniform rational B-splines (NURBS). The key of this algorithm is replacing the traditional linear acceleration–deceleration with flexible NURBS acceleration–deceleration. Based on the linear acceleration–deceleration algorithm, the control points of the NURBS curve are confirmed, and the final velocity of the polishing wheel center is solved using the Preston equation. With jerk continuity and limitations of the servo system, nonlinear equations are constructed, and the weighting factors corresponding to the control points are obtained. Cubic velocity control equations can be derived from the obtained feature parameters, which include the final velocity, control points, weighting factors and knot vectors. Based on the proposed NURBS acceleration–deceleration algorithm, a fourth-order Runge–Kutta formula was used to obtain the initial points, and the Milne–Hamming equation was used to predict and correct the next point. The predictor-corrector interpolation algorithm for parametric trajectory was implemented during the polishing process. The experimental results indicate that the proposed approach guarantees limited fluctuations of the relative velocity at contact points and ensure smoother velocity changes at dangerous points.

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