Regulatory actions of human stretch reflex

Crago, P.E.; Houk, James C.; Hasan, Ziaul

doi:10.1152/jn.1976.39.5.925

Cited by 613 publications

(241 citation statements)

References 33 publications

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“…The reaction time for each subject was taken to be the minimum latency of EMG onset following each perturbation. Since the responses were simple and independent of the direction of motor movement, they were likely to be pre-programmed, triggered reactions (Crago et al 1976). …”

Section: Protocolmentioning

confidence: 99%

Stretch reflex coupling between the hip and knee: implications for impaired gait following stroke

2008

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Individuals with hemiparetic stroke often exhibit an abnormal coupling between the frontal plane of the hip and saggital plane of the knee during gait. The purpose of this study was to determine if stretch sensitive reflexes, which are known to be altered following stroke, exhibit similar coupling between the muscles of the hip and knee in the post-stroke population. Eighteen subjects were recruited for this study including ten with hemiparesis resulting from stroke and eight unimpaired, age-matched controls. A servomotor was used to apply ramp and hold perturbations to both the hip and knee joints in separate sessions and electromyographic activity was recorded in eight muscles of the lower limb. Hip abduction perturbations elicited abnormal activation in rectus femoris (RF) in seven of ten stroke subjects with amplitudes ranging from 3.2 to 12.5% of the maximum voluntary contraction (MVC). Only two of eight control subjects exhibited any activity in RF and these responses were only 2.1 and 2.7% of MVC. To determine if the responses in the stroke group were a result of muscle stretch, a musculoskeletal model was used to simulate the experimental abduction perturbations and estimate muscle length changes. The simulation revealed that RF should be shortened by the perturbations and this suggests that the response was not likely due to direct stretch. Moreover, knee flexion perturbations elicited responses in the hip adductors (AL) with a mean amplitude of 5.1 ± 3.8% of MVC across all stroke subjects while no significant responses were recorded in controls. The presence of a reciprocal, reflex-mediated coupling between RF and AL following stroke suggests

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Section: Protocolmentioning

confidence: 99%

Stretch reflex coupling between the hip and knee: implications for impaired gait following stroke

2008

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“…An additional potential source of information for the corrective system might be proprioceptive input from the limb (see dotted arrow). It has been suggested that proprioceptive information can modify EMG responses with a delay of only 70 msec (Crago et al, 1976).…”

Section: Correcting Erroneous Responsesmentioning

confidence: 99%

Time Course of Error Detection and Correction in Humans: Neurophysiological Evidence

2002

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Using event-related brain potentials, the time course of error detection and correction was studied in healthy human subjects. A feedforward model of error correction was used to predict the timing properties of the error and corrective movements. Analysis of the multichannel recordings focused on (1) the error-related negativity (ERN) seen immediately after errors in response-and stimulus-locked averages and (2) on the lateralized readiness potential (LRP) reflecting motor preparation. Comparison of the onset and time course of the ERN and LRP components showed that the signs of corrective activity preceded the ERN. Thus, error correction was implemented before or at least in parallel with the appearance of the ERN component. Also, the amplitude of the ERN component was increased for errors, followed by fast corrective movements. The results are compatible with recent views considering the ERN component as the output of an evaluative system engaged in monitoring motor conflict.

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“…However, there remains controversy regarding the specificity of its modulation and the pathways that regulate this modulation. In particular, it has been suggested that the apparent facilitation of response amplitude when subjects are preparing to oppose a perturbation arises through an increase in the level of activation of the target muscle prior to the stretch (Capaday et al 1994), or that it represents the initial components of a triggered (Crago et al 1976) or voluntary (Rothwell et al 1980;Hallett et al 1981) reaction in the M2 time period.…”

Section: Introductionmentioning

confidence: 99%

The effect of task instruction on the excitability of spinal and supraspinal reflex pathways projecting to the biceps muscle

2006

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There is controversy within the literature regarding the influence of task instruction on the size of the long-latency stretch reflex (M2) elicited by a joint displacement. The aim of this study was to investigate if the previously reported task-dependent modulation of the M2 is specific to the M2 or can be explained by an early release of the intended voluntary response. We took advantage of the fact that the M2 is absent when the duration of the applied perturbation is less than a critical time period. This allowed us to examine modulation of muscle activity with and without the contribution of the M2. In addition, we applied transcranial magnetic stimulation (TMS) over the primary motor cortex to examine the modulation of corticomotor excitability with task instruction. Elbow joint extension displacements were used to elicit a stretch reflex in the biceps muscle. Subjects were instructed to "do not intervene" (DNI) with the applied perturbation, or to oppose the perturbation by activating the elbow flexors in response to the perturbation (FLEX). Electromyographic (EMG) activity in the time period corresponding to the M2 was significantly facilitated in the FLEX task instruction both with and without the presence of the M2. Motor evoked potentials (MEPs) elicited by TMS were also facilitated during the FLEX condition in the absence of the M2. EMG and MEP responses were not facilitated until immediately prior to the onset of the M2. Paired-pulse TMS revealed a significant reduction in short-interval intracortical inhibition (SICI) during the M2 response, but the level of SICI was not altered by the task instruction. We conclude that the taskdependent modulation of the biceps M2 results, at least in part, from an early release of the prepared movement and is accompanied by an increase in corticospinal excitability that is not specific to the M2 pathway. Task-dependent modulation of the response cannot be explained by an alteration in the excitability of intracortical inhibitory circuits.

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Regulatory actions of human stretch reflex

Cited by 613 publications

References 33 publications

Stretch reflex coupling between the hip and knee: implications for impaired gait following stroke

Stretch reflex coupling between the hip and knee: implications for impaired gait following stroke

Time Course of Error Detection and Correction in Humans: Neurophysiological Evidence

The effect of task instruction on the excitability of spinal and supraspinal reflex pathways projecting to the biceps muscle

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