Motion Feedback Research Articles

Delayed retinal feedback of eye movements: a dynamic basis of perceptual disabilities.

Delayed retinal feedback of eye movements: a dynamic basis of perceptual disabilities.

Processing of visual feedback in rapid movements.

Processing of visual feedback in rapid movements.

Scalene and sternomastoid muscle function.

Scalene and sternomastoid muscle function.

ANGULAR DISPLACEMENT OF VISUAL FEEDBACK IN MOTION AND LEARNING.

The main hypothesis was that angular displacement of the visual feedback of motion produces no disturbance of behavior within a limited “normal” range, but that a breakdown angle can be found beyond this range which will produce disturbance in motion control in proportion to the magnitude of the feedback displacement. Experimental results concerning maze tracing and circle drawing specifically supported the hypothesis. In circle drawing, both compensatory visual displacement errors and direct motor error in control of the pattern of motion conformed to the theoretical assumptions. In addition, data on learning in the two tasks conformed to theoretical assumptions that specific sensory-feedback factors determine differences in motor learning and that the spatial properties of such feedback determine the level of performance during learning. The guiding hypothesis was derived from a neurogeometric conception of brain function, which assumes that each internuncial cell acts as a space detector to record the angular difference between a given neural state of a movement and its sensory feedback. The data contribute positively to our understanding of the brain mechanism of motion and of the sensory process as a neurogeometric detector system. The experiments also define the significance of the methods of sensory-feedback analysis in disclosing the nature of intrinsic geometric relationships between the sensory and motor systems that determine learning and the organization of motion.

A CRITICAL PERIOD IN MATURATION OF PERFORMANCE WITH SPACE-DISPLACED VISION.

This research rests two specific hypotheses of neurogeometric theory that a critical period of maturation of space-displaced visual feedback in behavior occurs in childhood, and that a differential organization of inverted, reversed, and inverted-reversed visual feedback in motion will be found at the time when children are first capable of giving compensatory response to the geometric disorientation of vision. Thirty-six right-handed boys between the ages of 9.5 yr. and 13.5 yr. were tested in the different motions under conditions of normal, reversed, inverted, and inverted-reversed visual feedback. The results confirmed both main hypotheses. Ss younger than Age 12 consistently failed to perform the drawing tasks with inverted visual feedback while older Ss seldom failed. In keeping with theoretical expectations the results also showed that, when the different inverted and reversed feedback conditions could be performed, the response to the inverted feedback conditions was poorest, while that to the reversed condition was the most effective.

Maturation of performance with space-displaced vision.

This study tests two specific hypotheses of neurogeometric theory: that acritical period in maturation of space-displaced visual feedback in behavioroccurs in childhood, and that a differential organization of inverted, reversed, and inverted-reversed visual feedback in motion will be found at the time when children are first capable of giving compensatory response to the spatial disorientatiop of vision. In keeping with theoretical expectations theresults showed that when the different inverted and reversed feedback conditions could be performed, the response to the inverted feedback condition wasthe poorest, while that to the reversed condition was the most effective.

Theory of motional feedback

In motional feedback the mechanical vibrations of the loudspeaker cone are the source of the feedback voltage. Feedback then improves the over-all response characteristic and reduces the total distortion. The theory of this method is presented here in a simplified, though enlightening, way. The treatment is based on an unorthodox theorem on impedance conversion by feedback.

Stabilized Feedback Light-Valve<!--<xref ref-type="other" rid="fn1-10.5594_J09917">*</xref>-->

Feedback affords controlled and undistorted damping of light-valve resonance. All electromechanical devices can be regarded as feedback circuits if their motional impedance is interpreted as a feedback counter-emf. Auxiliary amplification of this counter-emf produces stabilized motional feedback. Depending on whether the amplifier counter-emf is proportional to amplitude, velocity, or acceleration, the feedback tends to flatten amplitude, velocity, or acceleration response characteristic. The light-valve is a mechanically resonant device operated on an amplitude basis but with a velocity counter-emf. Velocity feedback increases the effective damping of the light-valves; reactive components in the electrical driving impedance and in the feedback-gain tend to shift the resonance frequency. At 0.71 of critical damping the steady-state frequency characteristic is peakless and the valve follows transient impulses quickly with only 6 per cent overshooting. The maximum “bucking power” opposed to the valve motion by the feedback amplifier occurs at 0.58 of ribbon resonance and is 8 db less than the low-frequency power of the driving amplifier. — An amplifier is described that has been designed in accordance with the theory for application of stabilized feedback to commercial light-valves.