Postactivation depression and recovery of reflex transmission during repetitive electrical stimulation of the human tibial nerve

Clair, J. M.; Anderson-Reid, Jamie M.; Graham, Caitlin M.; Collins, David F.

doi:10.1152/jn.00932.2010

Cited by 30 publications

(31 citation statements)

References 52 publications

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“…Periodic PRM reflex modulation generated in a single muscle group showed that the mechanisms modulating the excitability of the respective motoneuron pool did not require the occurrence of such a pattern in other muscles (cf. Clair et al 2011). However, prevalence, consistency, and attenuation were significantly higher when the periodic patterns occurred in pairs of related muscle groups.…”

Section: Discussionmentioning

confidence: 85%

Periodic modulation of repetitively elicited monosynaptic reflexes of the human lumbosacral spinal cord

Hofstoetter

Danner

Freundl

et al. 2015

Journal of Neurophysiology

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Hofstoetter US, Danner SM, Freundl B, Binder H, Mayr W, Rattay F, Minassian K. Periodic modulation of repetitively elicited monosynaptic reflexes of the human lumbosacral spinal cord. J Neurophysiol 114: 400 -410, 2015. First published April 22, 2015 doi:10.1152/jn.00136.2015.-In individuals with motor-complete spinal cord injury, epidural stimulation of the lumbosacral spinal cord at 2 Hz evokes unmodulated reflexes in the lower limbs, while stimulation at 22-60 Hz can generate rhythmic burstlike activity. Here we elaborated on an output pattern emerging at transitional stimulation frequencies with consecutively elicited reflexes alternating between large and small. We analyzed responses concomitantly elicited in thigh and leg muscle groups bilaterally by epidural stimulation in eight motor-complete spinal cord-injured individuals. Periodic amplitude modulation of at least 20 successive responses occurred in 31.4% of all available data sets with stimulation frequency set at 5-26 Hz, with highest prevalence at 16 Hz. It could be evoked in a single muscle group only but was more strongly expressed and consistent when occurring in pairs of antagonists or in the same muscle group bilaterally. Latencies and waveforms of the modulated reflexes corresponded to those of the unmodulated, monosynaptic responses to 2-Hz stimulation. We suggest that the cyclical changes of reflex excitability resulted from the interaction of facilitatory and inhibitory mechanisms emerging after specific delays and with distinct durations, including postactivation depression, recurrent inhibition and facilitation, as well as reafferent feedback activation. The emergence of large responses within the patterns at a rate of 5.5/s or 8/s may further suggest the entrainment of spinal mechanisms as involved in clonus. The study demonstrates that the human lumbosacral spinal cord can organize a simple form of rhythmicity through the repetitive activation of spinal reflex circuits.

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Section: Discussionmentioning

confidence: 85%

Periodic modulation of repetitively elicited monosynaptic reflexes of the human lumbosacral spinal cord

Hofstoetter

Danner

Freundl

et al. 2015

Journal of Neurophysiology

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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: 76%

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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“…As was expected, in the healthy group, the ratio of test/conditioning H-reflex was significantly Ͻ1.0 up to 300 ms. However, it is known that the depression of the test H-reflex can last up to several seconds after the conditioning stimulation (Clair et al 2011;Crone and Nielsen 1989;Robertson and Koceja 2003;Robertson et al 2012). With our new method of using a conditioning H-reflex of variable size for the PRD method, a nonlinear pattern emerged in the healthy group; increasing the size of the conditioning H-reflex exponentially decreased that of the test H-reflex.…”

Section: Discussionmentioning

confidence: 99%

Characteristics of preceding Ia activity on postactivation depression in health and disease

Tahayori

Koceja

2015

Journal of Neurophysiology

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Previous activation of the soleus Ia afferents causes a depression in the amplitude of the H-reflex. This mechanism is referred to as postactivation depression (PAD) and is suggested to be presynaptically mediated. With the use of a paired reflex depression paradigm (eliciting two H-reflexes with conditioning-test intervals from 80 ms to 300 ms), PAD was examined in a group of healthy individuals and a group of hemiplegic patients. Healthy individuals showed substantial depression of the test H-reflex at all intervals. Although the patient group showed substantially less depression at all intervals, increasing the interval between the two reflexes sharply reduced the depression. In a separate experiment, we varied the size of the conditioning H-reflex against a constant test H-reflex. In healthy individuals, by increasing the size of the conditioning H-reflex, the amplitude of the test H-reflex exponentially decreased. In the patient group, however, this pattern was dependent on the conditioning-test interval; increasing the size of the conditioning H-reflex caused an exponential decrease in the size of the test reflex at intervals shorter than 150 ms. This pattern was similar to that of healthy individuals. However, conducting the same protocol at a longer interval (300 ms) in these patients resulted in an abnormal pattern (instead of an exponential decrease in the size of the test reflex, exaggerated responses were observed). Fisher discriminant analysis suggested that these two patterns (which differed only in the timing between the two stimuli) were substantially different from each other. Therefore, it is suggested that the abnormal pattern of PAD in hemiplegic stroke patients could be a contributing factor for the pathophysiology of spasticity.

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Postactivation depression and recovery of reflex transmission during repetitive electrical stimulation of the human tibial nerve

Cited by 30 publications

References 52 publications

Periodic modulation of repetitively elicited monosynaptic reflexes of the human lumbosacral spinal cord

Periodic modulation of repetitively elicited monosynaptic reflexes of the human lumbosacral spinal cord

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

Characteristics of preceding Ia activity on postactivation depression in health and disease

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