The illusory perception of movement caused by angular acceleration and by centrifugal force during flight. II. Visually perceived motion and displacement of a fixed target during turns.

1948 ◽  
Vol 38 (3) ◽  
pp. 298-309 ◽  
Author(s):  
Brant Clark ◽  
Ashton Graybiel ◽  
Kenneth MacCorquodale
Keyword(s):  
Centrifugal Force ◽  
Angular Acceleration ◽  
Fixed Target ◽  
Illusory Perception ◽  
Perceived Motion

Evaluation of human dynamic contraction by phonomyography

1992 ◽  
Vol 73 (6) ◽  
pp. 2567-2573 ◽  
Author(s):  
M. Petitjean ◽  
B. Maton ◽  
J. C. Cnockaert
Keyword(s):  
Linear Relationship ◽  
Biceps Brachii ◽  
Muscle Tension ◽  
Angular Acceleration ◽  
Fixed Target ◽  
Acceleration Phase ◽  
Dynamic Contraction ◽  
Linear Relationships ◽  
Integrated Emg ◽  
Muscle Contractile

Phonomyogram (PMG, or acoustic myogram) is known to increase with force in isometric contractions. We investigated this relationship for dynamic contractions against different inertias. PMG and surface electromyogram (EMG) from biceps brachii and brachioradialis muscles were simultaneously recorded with the angular acceleration of elbow flexions. These were self-initiated movements (30 degrees) toward a fixed target and performed against two different inertias. PMG and EMG were integrated from the onset of the signal to the end of the acceleration phase. Phono- and electromechanical delays were also measured. For integrated EMG (iEMG), there was a linear relationship between integrated PMG (iPMG) and force, the slope of which did not depend on inertia. There was also a linear relationship between iPMG or iEMG and angular acceleration, with a higher slope for the highest inertia condition. There was also a family of linear relationships between iPMG or iEMG and angular acceleration, and their slopes depended on inertia. Measurements of the phono- and electromechanical delays showed that onset of PMG followed that of EMG but preceded onset of acceleration. It is suggested that PMG expresses tension of the underlying muscle contractile elements. Given the simplicity of the PMG method, we conclude that PMG allows convenient evaluation of muscle tension during human dynamic contraction.

scholarly journals Rotation Experiments with Blind Goldfish

1957 ◽  
Vol 34 (2) ◽  
pp. 259-275
Author(s):  
F. R. HARDEN JONES
Keyword(s):  
Angular Velocity ◽  
Centrifugal Force ◽  
Constant Velocity ◽  
Angular Acceleration ◽  
Semicircular Canals ◽  
Mechanical Stimulus ◽  
Constant Angular Velocity ◽  
Water Current

1. Blind goldfish react to rotation at constant angular velocity by swimming against the direction of rotation so as to maintain, on the whole, the same orientation or bearing relative to earth. 2. The lowest angular velocity to which the fish appear to react is below 10°/sec. For the best performers the threshold is about 3°/sec. 3. The stimulus to which the fish responds is not one of contact, initial swirl or water current (when the turntable gets under way), variation in turntable velocity or centrifugal force. 4. The semicircular canals are probably the sensory channels through which a fish is able to detect rotation at constant velocity and the mechanical stimulus to which it responds is probably an angular acceleration. How the fish becomes aware of angular accelerations during rotation at constant velocity is not yet understood.

Effect of angular acceleration on the localization performance of a remembered target

2005 ◽  
Vol 15 (2) ◽  
pp. 81-92
Author(s):  
Frank Schmäl ◽  
Barbara Glitz ◽  
Oliver Thiede ◽  
Wolfgang Stoll
Keyword(s):  
Angular Acceleration ◽  
Vestibular Stimulation ◽  
Slow Phase ◽  
Fixed Target ◽  
Pointing Error ◽  
Ocular Reflex ◽  
Caloric Vestibular Stimulation ◽  
Vestibulo Ocular Reflex ◽  
Localization Performance ◽  
Self Motion

Both the influence of a remembered “earth-fixed” target (RT) on the vestibulo-ocular reflex and the effect of “unilateral cold caloric vestibular stimulation” on the localization of a RT have previously been proved. As “unilateral caloric stimulation” is not a physiological stimulus, the aim of the present study was to analyze whether even physiological “bilateral vestibular stimulation” (rotation) is able to affect the RT position. The pointing error (PE) towards an RT both without and following angular acceleration was investigated in 24 healthy volunteers. Postrotatory nystagmus response was recorded by electronystagmography. Evaluation parameters were “nystagmus frequency”, “total amplitude” and “velocity of the slow phase”; the horizontal and vertical PE. The fixation of an RT led to a significant reduction of about 28% in nystagmus amplitude compared to the test condition in darkness. “After rotatory stimulation” a systematic horizontal PE in the direction of the fast phase of the postrotatory nystagmus (direction of “illusory self-rotation”) occurred and the magnitude of this PE increased significantly compared to the test situation “without vestibular stimulation”, but showed only a non-uniform negative correlation with two of the nystagmus parameters. It has to be concluded that “after rotatory stimulation”, in contrast to “unilateral cold caloric vestibular stimulation”, the subjective sense of “illusory self-motion” leads to a horizontal PE in the direction of the nystagmus fast phases.

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