Modulation of upper extremity motor evoked potentials by cutaneous afferents in humans

Kofler, Markus; Fuhr, Peter; Leis, A. Arturo; Glocker, Franz Xaver; Kronenberg, Martina F.; Wissel, Jörg; ̌Sťetkářová, Ivana

doi:10.1016/s1388-2457(01)00540-5

Cited by 56 publications

(56 citation statements)

References 28 publications

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“…That change in movement implicates longer lasting excitatory periods of In the present case, posterior columns as assessed by median nerve sensory evoked potentials were normal, while CSP, an inhibitory part of the flexor reflex, in the right hand was attenuated. Afferent impulses that generate the CSP are carried by A-delta fibers, which conduct nociceptive impulses on spinal interneurons, located in close proximity to the central canal [5,6,12]. These findings, together with the phenomenology of the myoclonus and its response to methadone, suggest a mechanism involving an intraspinal pathway, susceptible to nociceptive input and endorphin receptor activation.…”

Section: Sollberger P Fuhrmentioning

confidence: 87%

Flexor myoclonus of the arm due to posttraumatic cervico-thoracic syringomyelia

Sollberger

Fuhr

2008

J Neurol

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Section: Sollberger P Fuhrmentioning

confidence: 87%

Flexor myoclonus of the arm due to posttraumatic cervico-thoracic syringomyelia

Sollberger

Fuhr

2008

J Neurol

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“…18,26,27 ). Part of this discrepancy favors distinct spinal inhibitory circuitry mediated by low-and high-threshold afferents 13,18,[28][29][30] , with the possibility that dopaminergic influence is exerted only on low-threshold afferent circuitry. The latter may contribute to the electrically evoked CSP (ref.…”

Section: Discussionmentioning

confidence: 99%

“…The latter may contribute to the electrically evoked CSP (ref. 28 ) due to concomitant activation of low-threshold afferents which inevitably occurs when applying electrical stimuli to peripheral nerves.…”

Section: Discussionmentioning

confidence: 99%

Cutaneous silent periods in multiple system atrophy

̌Sťetkářová¹,

Kofler²,

Majerová³

2015

BIOMED PAP

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Aim. The cutaneous silent period (CSP) is a spinal inhibitory reflex primarily mediated by A-delta fibers. Prolonged CSPs have been reported in patients with restless legs syndrome (RLS) and idiopathic Parkinson's disease (IPD). Dopaminergic medication normalizes the CSP, concurring with the effect of levodopa on CSPs. To date, CSPs have not been extensively studied in patients with multiple system atrophy (MSA). The purpose of this study was to confirm abnormal CSP findings in a group of MSA patients and to affirm the lack of influence of levodopa on CSPs during long-term treatment. Methods. We investigated 15 patients (4 males, 11 females, age 58-71 years) who fulfilled the diagnostic criteria for possible MSA. Thirteen patients had predominant parkinsonian symptoms (MSA-P), 2 had predominant cerebellar signs (MSA-C). We recorded CSPs in thenar muscles following noxious digit II stimulation. Sixteen healthy volunteers (6 males, 10 females, range 24-56 years) served as control subjects for CSP recordings. Results. Group average CSP onset was mildly delayed (P<0.01), whereas CSP end latency (P<0.001) were markedly delayed and CSP duration prolonged (P<0.001) in MSA patients compared to healthy controls. MSA patients on levodopa treatment did not differ in their CSPs from those without levodopa. The dose of levodopa did not correlate to any CSP parameter. Conclusion. The observed CSP prolongation corroborates previous findings in a limited number of MSA patients. The ineffectiveness of long-term levodopa on CSP abnormalities is consistent with its poor clinical effect in MSA.

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“…In test trials, the same stimuli were preceded by a single conditioning electrical stimulus of 0.5 ms duration delivered with ring electrodes to the 3 rd finger of the right hand at an intensity of 2 times perception threshold. For the conditioning of the MEP to TMS, we used interstimulus intervals (ISIs) of 20,25,30,35,40,45, and 50 ms, which have been shown to induce significant inhi- [34,36,58]. For the conditioning of the blink reflex, we used ISIs of 90, 100, and 110 ms, which have been shown to induce significant inhibition of the orbicularis oculi response to supraorbital nerve stimuli [21,63].…”

Section: General Experimental Proceduresmentioning

confidence: 99%

“…These features suggest an abnormal processing of sensory inputs, which could take place at various levels of the central nervous system [55]. Neurophysiological techniques can be used to assess how well a sensory input is integrated into motor circuits: somatosensory inputs induced by electrical activation of cutaneous nerves cause an inhibition of the motor evoked potentials (MEPs) generated by transcranial magnetic stimulation (TMS) in hand muscles [12,19,30,34,35,58,62], an effect that is believed to take place at various levels along the motor pathway, including the somatosensory cortex. Similarly, somatosensory inputs are able to suppress the reflex responses induced in the orbicularis oculi by electrical stimulation of the trigeminal nerve [17,21,63], an effect that is believed to take place on the trigeminal nerve afferents at the level of the brainstem.…”

Section: Introductionmentioning

confidence: 99%

Sensorimotor integration in patients with parkinsonian type multisystem atrophy

et al. 2005

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Sensorimotor integration is an essential feature of the central nervous system that contributes to the accurate performance of motor tasks. Some patients with multiple system atrophy with parkinsonian features (MSAp) exhibit clinical signs compatible with an abnormal central nervous system excitability to somatosensory inputs, such as action myoclonus or enhanced cutaneo-muscular reflexes. To investigate further the site where such dysfunction in sensorimotor integration takes place, we examined the inhibitory effects of a cutaneous afferent volley at two different levels of the motor system in 10 MSAp patients and in 10 age-matched healthy volunteers. Electrical digital nerve stimuli were given as the conditioning stimulus for the motor evoked potentials (MEP) elicited by transcranial magnetic stimulation in hand muscles, and for the blink reflex responses obtained in the orbicularis oculi muscles by supraorbital nerve stimulation. Intervals for the conditioning were 20 to 50 ms for the MEP and 90 to 110 ms for the blink reflex. The MEP was significantly inhibited in test trials in healthy volunteers, reaching a mean of 32% of the baseline values at the ISI of 35 ms. Significant inhibition occurred also in the blink reflex, in which the R2 response was a mean of 12% of baseline values at the ISI of 100 ms. The inhibitory effects were abnormally reduced in 8 patients on the MEP, and in 7 patients on the blink reflex. There were significant group differences between patients and control subjects in the size of the conditioned MEP and blink reflex. These results suggest that sensorimotor integration is abnormal in patients with MSAp in at least two central nervous system sites: the sensorimotor cortex, and the brainstem reticular formation.

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Modulation of upper extremity motor evoked potentials by cutaneous afferents in humans

Cited by 56 publications

References 28 publications

Flexor myoclonus of the arm due to posttraumatic cervico-thoracic syringomyelia

Flexor myoclonus of the arm due to posttraumatic cervico-thoracic syringomyelia

Cutaneous silent periods in multiple system atrophy

Sensorimotor integration in patients with parkinsonian type multisystem atrophy

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