Changes in presynaptic inhibition of afferents to propriospinal‐like neurones in man during voluntary contractions.

Burke, David; Graciès, Jean-Michel; Meunier, Sabine; Pierrot-Deseilligny, E

doi:10.1113/jphysiol.1992.sp019108

Cited by 53 publications

(22 citation statements)

References 18 publications

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“…Moreover, presynaptic inhibition of various origins can be expected to play a prominent role in the modulation of the effectiveness of the Ia monosynaptic inputs during isometric contraction of human forearm muscles (Berardelli et al 1987;Nakashima et al 1990;Burke et al 1992). If this occurs in the extensor carpi radialis muscles, it does not seem to alter the graded action of the afferent volleys evoked by tendon taps on wrist extensor motoneurones, which were found here to obey the "size principle".…”

mentioning

confidence: 65%

The “size principle” and synaptic effectiveness of muscle afferent projections to human extensor carpi radialis motoneurones during wrist extension

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Morin

et al. 1997

Exp Brain Res

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The question of whether muscle spindle afferents might control human motoneurone activity on the basis of the "size principle" during voluntary contraction was investigated by recording the discharge of single motor units (n = 196) in wrist extensor muscles while stimulating the homonymous muscle spindles by means of tendon taps. The mechanical stimuli were delivered with a constant post-spike delay of 80 ms so that the resulting afferent volleys could be expected to reach the motoneurones towards the end of the inter-spike interval (mean +/- SD duration: 124.7 +/- 11.9 ms). In the six subjects tested, the response probability was found to be significantly correlated with the motor units' functional parameters. Differences in twitch rise times, twitch amplitudes, recruitment thresholds and macro-potential areas were found to account for 18%, 9%, 6% and 2% of the differences in the response probability observed within the whole population of motor units tested. These differences could not be due to differences in firing rate for two reasons: first, the motor units were found to discharge with a similar range of inter-spike intervals whatever their functional characteristics; secondly, the weak positive correlation observed between the response probability and the motor unit firing rate showed parallel regression lines between the late-recruited fast-contracting motor units and the first-recruited slowly contracting motor units, but the y-intercept was significantly higher in the latter case. This confirmed that the responses of the first-recruited slowly contracting motor units tended to be larger whatever the firing rates. In most of the pairs tested in the same experiment, the motor units which had the lowest recruitment thresholds, longest contraction times, smallest contraction forces or smallest motor unit macro-potentials tended to produce the largest responses, which also had the longest latencies. Taking the response latency to be an index of a motoneurone's conduction velocity and therefore of its size, the data obtained with this index and with other functional indices such as the twitch rise times and amplitudes, the macro-potential areas and the recruitment thresholds-can be said to be fully consistent with the "size principle", as previously found in anaesthetized animals. It can be inferred that the presynaptic inhibition which is liable to take action during voluntary contraction does not seem to alter the graded distribution of the muscle afferent projections to human wrist extensor motoneurones.

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confidence: 65%

The “size principle” and synaptic effectiveness of muscle afferent projections to human extensor carpi radialis motoneurones during wrist extension

Schmied

Morin

et al. 1997

Exp Brain Res

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“…It is possible that, additionally, TMS inputs cause a transient decrease in the level of ongoing presynaptic control over Ia aVerent inputs (Valls-Solé et al 1994). Vibration-induced inhibition of the H reXex occurs at a presynaptic level, by activation of primary aVerent depolarization neurons, dendritic hyperpolarization or neurotransmitter depletion and Ca 2+ channel inactivation (Burke et al 1992;Rudomin 2009;Clair et al 2011). In some of our subjects, even if the vibrated H reXex was very small, it was strongly facilitated by TMS (such as in the case represented in Fig.…”

Section: Mechanisms Involved In the Generation Of The Wrst Phase Of Tmentioning

confidence: 93%

The effects of transcranial magnetic stimulation on vibratory-induced presynaptic inhibition of the soleus H reflex

et al. 2012

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A single-pulse transcranial magnetic stimulus (TMS) may induce contraction in many muscles of the body at the same time. This is specially the case when using the double-cone coil to obtain the motor evoked potentials in leg muscles. Even if intensity is kept below threshold for the soleus muscle, TMS induces facilitation of the soleus H reflex that is separated into two phases: the first, peaking at 10-20 ms and the second, peaking at 70-90 ms. We investigated the possibility that TMS-induced facilitation of the H reflex was related, at least in part, to the reafferentation volley reaching the alpha motoneuron after synchronized contraction of other muscles in the body. To test this hypothesis, we examined the effects of vibration on the TMS-induced facilitation of the soleus H reflex. As expected, vibration applied over the triceps tendon caused a significant reduction in H reflex amplitude: 42.4 ± 6.4 % of control values. When conditioned by TMS at intervals corresponding to the first phase, the H reflex was facilitated to the same extent in both conditions: with and without vibration. However, at intervals corresponding to the second facilitation phase, there was a significantly reduced facilitation with vibration. These differential effects of vibration on the two phases of the TMS-induced facilitation of the H reflex indicate a different mechanism for each facilitation phase. The first phase could result from direct corticospinal excitatory input, while the second phase might depend on inputs via Ia afferents from heteronymous muscles.

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“…Figure 4A (A) shows the marked long-lasting depression of the ECR H reflex evoked by a short train of stimuli to the median nerve; after a transient facilitation at 30 ms, this inhibition peaked at 60-100 ms and was over at 200 ms. When using a single shock to the median nerve, a similarly long-lasting inhibition was observed but two brief phases of reflex facilitation were superimposed on the inhibition at the 30 ms and at the 100-120 ms intervals (much as in experiments investigating the effect of radial stimulation on the FCR H reflex; Berardelli et al 1987;Burke, Gracies, Meunier & Pierrot-Deseilligny, 1992b). The long time course shown in Fig.…”

Section: Effects Of Sr Stimulation On the Transmission Of The Afferenmentioning

confidence: 95%

Non‐monosynaptic transmission of the cortical command for voluntary movement in man.

Burke

Graciès

Mazevet

et al. 1994

The Journal of Physiology

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103

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1. The possibility was investigated that, in man, some of the descending command for tonic voluntary wrist extension is transmitted to extensor motoneurones over a nonmonosynaptic pathway. 2. Stimulation of the cutaneous superficial radial nerve at 3 times perceptual threshold depressed the electromyogram (EMG) of extensor carpi radialis (ECR) and the discharge of single ECR motor units, both with a mean central delay of 4-2 ms. Such stimuli depressed the response to transcranial magnetic stimulation of the motor cortex, but had little effect on the H reflex. 3. The possibility that the relative sparing of the H reflex was due to an alteration in transmission of the afferent volley for the H reflex was excluded. 4. The central latency of the cutaneous-induced depression of the discharge of single motor units in biceps brachii (C5-C6) was shorter by about 1 ms than that of the more caudal wrist and finger extensor motor units. This suggests that the locus for the cutaneousinduced effects was spinal but above the cervical enlargement. 5. The pattern of EMG depression (evoked by superficial radial but not palmar stimuli, in wrist extensors but not wrist flexors) is that previously described for the presumed propriospinal system of human subjects. 6. It is concluded that a significant component of the voluntary command for tonic wrist extension reaches the relevant motoneurone pool via a non-monosynaptic pathway. It is suggested that the interposed neurones could be C3-C4 propriospinal neurones.

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Changes in presynaptic inhibition of afferents to propriospinal‐like neurones in man during voluntary contractions.

Cited by 53 publications

References 18 publications

The “size principle” and synaptic effectiveness of muscle afferent projections to human extensor carpi radialis motoneurones during wrist extension

The “size principle” and synaptic effectiveness of muscle afferent projections to human extensor carpi radialis motoneurones during wrist extension

The effects of transcranial magnetic stimulation on vibratory-induced presynaptic inhibition of the soleus H reflex

Non‐monosynaptic transmission of the cortical command for voluntary movement in man.

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