Patterns of recurrent excitation and mutual inhibition of cat Renshaw cells.

Ryall, R. W.

doi:10.1113/jphysiol.1981.sp013799

Cited by 34 publications

(20 citation statements)

References 13 publications

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“…6) does not produce considerable depression above that accounted for by afterhyperpolarization. This is in keeping with the expectation that mutual inhibition be strongest between Renshaw cells getting their respective excitatory inputs from antagonistic amotoneurones (Ryall 1981), whereas it should be relatively weak among Renshaw cells receiving their main input from homonymous motoneurones. Yet late (and strong) depression also occurs with activation of purely homonymous motor axons (Figs.…”

Section: Possible Causes Of Conditioning Effectssupporting

confidence: 52%

“…6J) with two exponentials (with time constants of the order of 30 and 100 ms), although not well so because of the scatter of their data. A contribution to depression could also come from mutual inhibition between Renshaw cells (Ryall 1970(Ryall , 1981. But if so, it is probably small because activation of a synergistic parallel input (Fig.…”

Section: Possible Causes Of Conditioning Effectsmentioning

confidence: 99%

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Time constants of facilitation and depression in Renshaw cell responses to random stimulation of motor axons

et al. 1988

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Summary. In 9 adult anaesthetized cats, 22 lumbosacral Renshaw cells recorded with NaCl-filled micropipettes were activated by random stimulation of ventral roots or peripheral nerves. The stimulus patterns had mean rates of 9.5-13 or 20-23 or 45 pulses per second and were pseudo-Poisson; short intervals below ca. 5 ms (except in two cases) were excluded. The Renshaw cell responses were evaluated by two kinds of peristimulus-time histograms (PSTHs). "Conventional" PSTHs were calculated by averaging the Renshaw cell discharge with respect to all the stimuli in a train. These PSTHs showed an early excitatory response which was often followed by a longer-lasting slight reduction of the discharge probability. These two response components were positively correlated. "Conditional" PSTHs were determined by averaging the Renshaw cell discharge with respect to the second ("test") stimulus in pairs of stimuli which were separated by varied intervals, 6. The direct effect of the first "conditional" response was subtracted from the excitation following the second ("test") stimulus so as to isolate the effect caused by the second stimulus per se. After such a correction, the effect of the first "conditioning" stimulus showed pure depression, pure facilitation or mixed facilitation/depression. Analysis of such conditioning curves yielded two time constants of facilitation (ranges: ca. 435 ms and 93-102 ms) and two of depression (ranges: ca. 7-25 ms and 50-161 ms). It is concluded that these time constants are compatible with processes of short-term synaptic plasticity known from other synapses. Other processes such as afterhyperpolarization and mutual inhibition probably are of less importance.

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Section: Possible Causes Of Conditioning Effectssupporting

confidence: 52%

Section: Possible Causes Of Conditioning Effectsmentioning

confidence: 99%

Time constants of facilitation and depression in Renshaw cell responses to random stimulation of motor axons

et al. 1988

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“…They were also excited by motoneurons of partial-synergist muscles (Eccles et al, 1954(Eccles et al, , 1961. They inhibited both partial-synergist motoneurons and true-antagonist Renshaw interneurons (Hultborn et al, 1979;Ryall, 1981).…”

Section: Spinal Circuitry Modelmentioning

confidence: 98%

Spinal-Like Regulator Facilitates Control of a Two-Degree-of-Freedom Wrist

Raphael

Tsianos²,

Loeb³

2010

Journal of Neuroscience

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The performance of motor tasks requires the coordinated control and continuous adjustment of myriad individual muscles. The basic commands for the successful performance of a sensorimotor task originate in "higher" centers such as the motor cortex, but the actual muscle activation and resulting torques and motion are considerably shaped by the integrative function of the spinal interneurons. The relative contributions of brain and spinal cord are less clear for reaching movements than for automatic tasks such as locomotion. We have modeled a two-axis, four-muscle wrist joint with realistic musculoskeletal mechanics and proprioceptors and a network of regulatory circuitry based on the classical types of spinal interneurons (propriospinal, monosynaptic Ia-excitatory, reciprocal Ia-inhibitory, Renshaw inhibitory, and Ib-inhibitory pathways) and their supraspinal control (via biasing activity, presynaptic inhibition, and fusimotor gain). The modeled system has a very large number of control inputs, not unlike the real spinal cord that the brain must learn to control to produce desired behaviors. It was surprisingly easy to program this model to emulate actual performance in four very different but well described behaviors: (1) stabilizing responses to force perturbations; (2) rapid movement to position target; (3) isometric force to a target level; and (4) adaptation to viscous curl force fields. Our general hypothesis is that, despite its complexity, such regulatory circuitry substantially simplifies the tasks of learning and producing complex movements.

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“…From the previous considerations, it is unlikely that postsynaptic factors account for this fact. A likely candidate for a possible mechanism is mutual inhibition between Renshaw cells (Ryall 1970(Ryall , 1981, which should be more easily recruited by synchronous events in two input channels than by disjunct events in each single input channel. To assume other possible presynaptic mechanisms such as interactions between axon collaterals impinging on a Ren- Fig.…”

Section: Conditioning Curvesmentioning

confidence: 99%

“…R2 These cells receive their main excitatory input from recurrent axon collaterals synapsing monosynaptically on them. A disynaptic inhibitory connection may be established via R3 other Renshaw cells (mutual inhibition : Ryall 1970: Ryall , 1981. It is very appealing to believe that this indirect route from two groups of motor axons to a Renshaw cell is opened particularly easily by synchronous impulses in the two input channels.…”

Section: Introductionmentioning

confidence: 99%

A method to estimate the effects of parallel inputs on neuronal discharge probability

et al. 1989

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Abstract. We here present a method to study the interaction of parallel neural input channels regarding their effects on a neurone. In particular, the method allows to disclose the effects of oligosynaptic pathways that may exist in parallel to direct monosynaptic connections to the cell. Two (or more) inputs (nerves) are stimulated with random patterns of stimuli. The response of the cell to these patterns is evaluated by the computation of peristimulus-time histograms (PSTHs). One of the two stimulus trains is selected as the one to yield reference events for the PSTH computation. From this stimulus train are selected those stimuli as reference events which are preceded, at defined mean intervals, by stimuli in the same or a parallel channel. These "conditioning" stimuli are determined (1) separately from each single stimulus train and (2) concomitantly from the two trains as events occurring simultaneously in both. The effects exerted by these various conditioning events on the effects of the "test" pulses on the cell response yield insights into the interactions between the two (or more) inputs. These methods are demonstrated on spinal Renshaw cells activated by independent random stimulation of two muscle nerves and on dorsal horn neurones responding to cutaneous nerve stimulation.

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Patterns of recurrent excitation and mutual inhibition of cat Renshaw cells.

Cited by 34 publications

References 13 publications

Time constants of facilitation and depression in Renshaw cell responses to random stimulation of motor axons

Time constants of facilitation and depression in Renshaw cell responses to random stimulation of motor axons

Spinal-Like Regulator Facilitates Control of a Two-Degree-of-Freedom Wrist

A method to estimate the effects of parallel inputs on neuronal discharge probability

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