The influence of different descending systems on the tonic stretch reflex in the cat

Feldman, Anatol G.; Orlovsky, G. N.

doi:10.1016/0014-4886(72)90091-x

Cited by 290 publications

(111 citation statements)

References 23 publications

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“…Such shifts have been shown to occur during voluntary arm movements in humans (Asatryan and Feldman 1965;Archambault et al 2005). It has also been shown in decerebrated cats that different descending and reflex systems shift the static force-length characteristic of hind limb muscles by changing their SR thresholds (Matthews 1959;Feldman and Orlovsky 1972;Nichols and Steeves 1986;Capaday et al 1995;Archambault et al 2005). Strikingly similar, in terms of shape, force-length characteristics were recorded in EOM of intact humans (Collins et al 1975).…”

Section: Possible Role Of the Sr In The Control Of Eye Movementsmentioning

confidence: 74%

A stretch reflex in extraocular muscles of species purportedly lacking muscle spindles

et al. 2007

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It is generally assumed that proprioceptive feedback plays a crucial role in limb posture and movement. However, the role of afferent signals from extraocular muscles (EOM) in the control of eye movement has been a matter of continuous debate. These muscles have atypical sensory receptors in several species and it has been proposed that they are not supported by stretch reXexes. We recorded electromyographic activity of EOM during passive rotations of the eye in sedated rats and squirrel monkeys and observed typical stretch reXexes in these muscles. Results suggest that there is a similarity in the reXexive control of limb and eye movement, despite substantial differences in their biomechanics and sensory receptors. Like in some limb skeletal muscles, the stretch reflex in EOM in the investigated species might be mediated by other lengthsensitive receptors, rather than muscle spindles.

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Section: Possible Role Of the Sr In The Control Of Eye Movementsmentioning

confidence: 74%

A stretch reflex in extraocular muscles of species purportedly lacking muscle spindles

et al. 2007

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“…Feldman and Orlovsky 42) found that descending signals adjust a specific neurophysiological variable, the threshold limb position at which relevant muscles are ready to be recruited when stretched. By shifting or simply resetting this threshold position, the brain may create the spatial frame of reference in which muscles are constrained to work without pre-determining how they should work, or to work without resolving inverse problems 43,44) .…”

Section: Posture-movement Paradoxmentioning

confidence: 99%

The old-but-new theories about human voluntary motor control

Suzuki

Wasaka

2012

JPFSM

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For more than a century, neuroscientists have debated the problem of how selfgenerated voluntary motor actions are executed without interference from sensory information elicited by the movements. In the 1950's, two theories were proposed: the corollary discharge theory by Sperry 1) and the efference copy theory by von Holst and Mittelstaedt 2) . They are essentially identical in proposing the necessity of specific neuronal mechanisms to suppress undesirable percepts or reflexes, both of which might disturb ongoing movements. However, this raises a simple question as to whether the control system always ignores sensory information whenever the intended movements are in progress. Here, we review recent findings and currently debated problems in corollary discharge theory.

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“…We assume that the stretch reflex plays a role in maintaining muscle's invariant spring-like property (Feldman and Orlovsky, 1972;Feldman, 1986).…”

Section: Spinal Computation Of Muscle Control Inputsmentioning

confidence: 99%

Analysis of an optimal control model of multi-joint arm movements

Lan

1997

Biological Cybernetics

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Abstract. In this paper, we propose a model of biological motor control for generation of goal-directed multi-joint arm movements, and study the formation of muscle control inputs and invariant kinematic features of movements. The model has a hierarchical structure that can determine the control inputs for a set of redundant muscles without any inverse computation. Calculation of motor commands is divided into two stages, each of which performs a transformation of motor commands from one coordinate system to another. At the first level, a central controller in the brain accepts instructions from higher centers, which represent the motor goal in the Cartesian space. The controller computes joint equilibrium trajectories and excitation signals according to a minimum effort criterion. At the second level, a neural network in the spinal cord translates the excitation signals and equilibrium trajectories into control commands to three pairs of antagonist muscles which are redundant for a two-joint arm. No inverse computation is required in the determination of individual muscle commands. The minimum effort controller can produce arm movements whose dynamic and kinematic features are similar to those of voluntary arm movements. For fast movements, the hand approaches a target position along a near-straight path with a smooth bell-shaped velocity. The equilibrium trajectories in X and ½ show an 'N' shape, but the end-point equilibrium path zigzags around the hand path. Joint movements are not always smooth. Joint reversal is found in movements in some directions. The excitation signals have a triphasic (or biphasic) pulse pattern, which leads to stereotyped triphasic (or biphasic) bursts in muscle control inputs, and a dynamically modulated joint stiffness. There is a fixed sequence of muscle activation from proximal muscles to distal muscles. The order is preserved in all movements. For slow movements, it is shown that a constant joint stiffness is necessary to produce a smooth movement with a bell-shaped velocity. Scaled movements can be reproduced by varying the constraints on the maximal level of excitation signals according to the speed of movement.When the inertial parameters of the arm are altered, movement trajectories can be kept invariant by adjusting the pulse height values, showing the ability to adapt to load changes. These results agree with a wide range of experimental observations on human voluntary movements.

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The influence of different descending systems on the tonic stretch reflex in the cat

Cited by 290 publications

References 23 publications

A stretch reflex in extraocular muscles of species purportedly lacking muscle spindles

A stretch reflex in extraocular muscles of species purportedly lacking muscle spindles

The old-but-new theories about human voluntary motor control

Analysis of an optimal control model of multi-joint arm movements

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