scholarly journals Voluntary Control of Human Jaw Stiffness

2005 ◽  
Vol 94 (3) ◽  
pp. 2207-2217 ◽  
Author(s):  
Douglas M. Shiller ◽  
Guillaume Houle ◽  
David J. Ostry
Keyword(s):  
Nervous System ◽  
Arm Movement ◽  
Vertical Axis ◽  
Voluntary Control ◽  
Robotic Device ◽  
Movement Accuracy ◽  
Human Arm ◽  
Applied Forces ◽  
Stiffness Control

Recent studies of human arm movement have suggested that the control of stiffness may be important both for maintaining stability and for achieving differences in movement accuracy. In the present study, we have examined the voluntary control of postural stiffness in 3D in the human jaw. The goal is to address the possible role of stiffness control in both stabilizing the jaw and in achieving the differential precision requirements of speech sounds. We previously showed that patterns of kinematic variability in speech are systematically related to the stiffness of the jaw. If the nervous system uses stiffness control as a means to regulate kinematic variation in speech, it should also be possible to show that subjects can voluntarily modify jaw stiffness. Using a robotic device, a series of force pulses was applied to the jaw to elicit changes in stiffness to resist displacement. Three orthogonal directions and three magnitudes of forces were tested. In all conditions, subjects increased the magnitude of jaw stiffness to resist the effects of the applied forces. Apart from the horizontal direction, greater increases in stiffness were observed when larger forces were applied. Moreover, subjects differentially increased jaw stiffness along a vertical axis to counteract disturbances in this direction. The observed changes in the magnitude of stiffness in different directions suggest an ability to control the pattern of stiffness of the jaw. The results are interpreted as evidence that jaw stiffness can be adjusted voluntarily, and thus may play a role in stabilizing the jaw and in controlling movement variation in the orofacial system.

scholarly journals Effects of Human Arm Impedance on Dynamics Learning and Generalization

2009 ◽  
Vol 101 (6) ◽  
pp. 3158-3168 ◽  
Author(s):  
Mohammad Darainy ◽  
Andrew A. G. Mattar ◽  
David J. Ostry
Keyword(s):  
Motor Learning ◽  
Force Field ◽  
Strong Correlation ◽  
Transfer Of Learning ◽  
Kinematic Error ◽  
Robotic Device ◽  
Human Arm ◽  
Applied Forces ◽  
Static Conditions ◽  
Dynamic Perturbation

Previous studies have demonstrated anisotropic patterns of hand impedance under static conditions and during movement. Here we show that the pattern of kinematic error observed in studies of dynamics learning is associated with this anisotropic impedance pattern. We also show that the magnitude of kinematic error associated with this anisotropy dictates the amount of motor learning and, consequently, the extent to which dynamics learning generalizes. Subjects were trained to reach to visual targets while holding a robotic device that applied forces during movement. On infrequent trials, the load was removed and the resulting kinematic error was measured. We found a strong correlation between the pattern of kinematic error and the anisotropic pattern of hand stiffness. In a second experiment subjects were trained under force-field conditions to move in two directions: one in which the dynamic perturbation was in the direction of maximum arm impedance and the associated kinematic error was low and another in which the perturbation was in the direction of low impedance where kinematic error was high. Generalization of learning was assessed in a reference direction that lay intermediate to the two training directions. We found that transfer of learning was greater when training occurred in the direction associated with the larger kinematic error. This suggests that the anisotropic patterns of impedance and kinematic error determine the magnitude of dynamics learning and the extent to which it generalizes.

The role of the sympathetic and sensory nervous system in peritoneal endometriotic lesions

2011 ◽  
Vol 71 (10) ◽  
Author(s):  
J Arnold ◽  
ML Barcena de Arellano ◽  
C Rüster ◽  
A Schneider ◽  
S Mechsner
Keyword(s):  
Nervous System ◽  
Sensory Nervous System

Thyroid hormone-catecholamine interrelationships during exposure to cold

1981 ◽  
Vol 97 (1) ◽  
pp. 91-97 ◽  
Author(s):  
H. Storm ◽  
C. van Hardeveld ◽  
A. A. H. Kassenaar
Keyword(s):  
Nervous System ◽  
Plasma Concentration ◽  
Thyroid Hormone ◽  
Sympathetic Nervous System ◽  
Plasma Levels ◽  
Surgical Procedure ◽  
Exposure To Cold ◽  
Basal Plasma ◽  
Sympathetic Nervous

Abstract. Basal plasma levels for adrenalin (A), noradrenalin (NA), l-triiodothyronine (T3), and l-thyroxine (T4) were determined in rats with a chronically inserted catheter. The experiments described in this report were started 3 days after the surgical procedure when T3 and T4 levels had returned to normal. Basal levels for the catecholamines were reached already 4 h after the operation. The T3/T4 ratio in plasma was significantly increased after 3, 7, and 14 days in rats kept at 4°C and the same holds for the iodide in the 24-h urine after 7 and 14 days at 4°C. The venous NA plasma concentration was increased 6- to 12-fold during the same period of exposure to cold, whereas the A concentration remained at the basal level. During infusion of NA at 23°C the T3/T4 ratio in plasma was significantly increased after 7 days compared to pair-fed controls, and the same holds for the iodide excretion in the 24-h urine. This paper presents further evidence for a role of the sympathetic nervous system on T4 metabolism in rats at resting conditions.

The role of autonomic nervous system in progression of school myopia in children

2019 ◽  
pp. 133-138
Author(s):  
D.A. Dubko ◽  
◽  
G.P. Smoliakova ◽  
O.I. Kashura ◽  
O.V. Mazurina ◽  
...  
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Autonomic Nervous ◽  
School Myopia

ROLE OF THE CENTERS OF THE CENTRAL AND INDEPENDENT CONTOURS IN REGULATION OF THE INTIMATE RHYTHM AT PERFORMANCE OF STANDARD PHYSICAL ACTIVITY

ASJ. ◽  
2020 ◽  
Vol 2 (40) ◽  
pp. 22-31
Author(s):  
A.B. Shutov ◽  
A.A. Matskanjuk ◽  
C. V. Korney
Keyword(s):  
Physical Activity ◽  
Nervous System ◽  
Analysis Time ◽  
Vegetative Nervous System ◽  
Distinctive Features

Use of a method of share tendencies in the analysis time of some R-R intervals of the electrocardiogram after performance of 20 knee-bends and after 1 minute of restoration has allowed to establish a role of the centers of vegetative nervous system in restoration of a rhythm of heart at 4-th level of dynamic hierarchy. After 20-ти knee-bends and through 1 minutes of restoration the maximum vegetative centers of the central contour dominate. In interaction of the central and independent contours each center entering into them is characterized with distinctive features of dynamics which are shown in an increasing role of the centers of an independent contour after 1 minute of restoration.

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