Changes of Electrically Elicited Reflexes in Hand and Forearm Muscles in Man

Im, Tarkka; Ta, Larsen

doi:10.1097/00002060-198710000-00010

Cited by 6 publications

(2 citation statements)

References 14 publications

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“…The onset latencies of the excitatory responses corresponded well with the latencies previously reported in small hand muscles (Caccia et al 1973, Garnett & Stephens 1980). The excitatory responses always occurred before the voluntary reaction time and thus can be considered reflectory responses (Tarkka & Larsen 1986).…”

Section: Discussionmentioning

confidence: 99%

Short and long latency reflex responses elicited by electrical and mechanical stimulation in human hand muscle

Tarkka

Larsen

1986

Acta Physiologica Scandinavica

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The relationship between electrically and mechanically induced reflex responses in the rectified, averaged surface electromyogram of the first interosseus dorsalis muscle was examined in 18 healthy human subjects. Both methods evoked identifiable short and long latency reflex responses. The onset latencies for short latency reflexes with electrical and mechanical stimulations were 30.6 ms (+/- 2.2 ms) and 28.9 ms (+/- 2.2 ms) and for long latency reflexes 50.0 ms (+/- 2.8 ms) and 51.2 ms (+/- 5.2 ms), respectively. The correlation of the onset latencies of the reflexes revealed significant correspondence between the electrical and mechanical methods implying at least partly mutual mechanisms.

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Section: Discussionmentioning

confidence: 99%

Short and long latency reflex responses elicited by electrical and mechanical stimulation in human hand muscle

Tarkka

Larsen

1986

Acta Physiologica Scandinavica

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“…After a seminal study by Hammond in 1956(Hammond, 1956, several investigators have utilized a limb perturbation paradigm to investigate the physiological mechanisms subserving the muscle stretch responses to the externally applied loads (Allum, 1975;Crago et al, 1976;Evarts and Granit, 1976;Thomas et al, 1977;Kurtzer, 2015;Zonnino et al, 2019). In these paradigms, the muscle responses including the LLRs are recorded through surface electromyography (EMG) activity evoked in the muscle stretched by an imposed angular joint displacement induced by a mechanical perturbation of known and controllable characteristics (Rothwell et al, 1980;Tarkka and Larsen, 1987;Cody and Plant, 1989;Matthews, 1989Matthews, , 1993Noth et al, 1991;Kurtzer, 2015).…”

Section: Introductionmentioning

confidence: 99%

Effects of Perturbation Velocity, Direction, Background Muscle Activation, and Task Instruction on Long-Latency Responses Measured From Forearm Muscles

Weinman

Arfa-Fatollahkhani

Zonnino

et al. 2021

Front. Hum. Neurosci.

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The central nervous system uses feedback processes that occur at multiple time scales to control interactions with the environment. The long-latency response (LLR) is the fastest process that directly involves cortical areas, with a motoneuron response measurable 50 ms following an imposed limb displacement. Several behavioral factors concerning perturbation mechanics and the active role of muscles prior or during the perturbation can modulate the long-latency response amplitude (LLRa) in the upper limbs, but the interactions among many of these factors had not been systematically studied before. We conducted a behavioral study on thirteen healthy individuals to determine the effect and interaction of four behavioral factors – background muscle torque, perturbation direction, perturbation velocity, and task instruction – on the LLRa evoked from the flexor carpi radialis (FCR) and extensor carpi ulnaris (ECU) muscles after velocity-controlled wrist displacements. The effects of the four factors were quantified using both a 0D statistical analysis on the average perturbation-evoked EMG signal in the period corresponding to an LLR, and using a timeseries analysis of EMG signals. All factors significantly modulated LLRa, and their combination nonlinearly contributed to modulating the LLRa. Specifically, all the three-way interaction terms that could be computed without including the interaction between instruction and velocity significantly modulated the LLR. Analysis of the three-way interaction terms of the 0D model indicated that for the ECU muscle, the LLRa evoked when subjects are asked to maintain their muscle activation in response to the perturbations was greater than the one observed when subjects yielded to the perturbations (p < 0.001), but this effect was not measured for muscles undergoing shortening or in absence of background muscle activation. Moreover, higher perturbation velocity increased the LLRa evoked from the stretched muscle in presence of a background torque (p < 0.001), but no effects of velocity were measured in absence of background torque. Also, our analysis identified significant modulations of LLRa in muscles shortened by the perturbation, including an interaction between torque and velocity, and an effect of both torque and velocity. The time-series analysis indicated the significance of additional transient effects in the LLR region for muscles undergoing shortening.

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Concurrent changes in shortening reaction latency and reaction time of forearm muscles in post-stroke patients

et al. 2006

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The objective was to confirm the hypothesis that shortening reaction (ShoRe), normally occurring on forcibly shortening a muscle, is depressed or delayed in post-stroke patients. Eight post-stroke patients and ten age-matched normal subjects had a 50 degrees wrist extension or flexion induced by a torque-motor in the affected and the non-affected upper limb. Patients were instructed either not to intervene or to assist displacement (reaction-time condition, RT). Frequency of occurrence and latency of stretch reflex (SR) and ShoRe, and RTs were measured from the electromyograms (EMG) of wrist flexor (FCR) and extensor (ECR) muscles. SR had higher than normal frequency in both muscles. ShoRe disappeared in ECR on the affected side but had normal frequency in FCR of both sides. ShoRe latency was prolonged in FCR and ECR, in both affected and unaffected sides. RTs were prolonged in both FCR and ECR, in both affected and unaffected sides. Across all patients, RTs and ShoRe latencies in the FCR were correlated. Neither RTs nor ShoRe latencies were correlated to Ashworth score. RTs were inversely correlated to Medical Research Council scores. The decreased and delayed ShoRe in post-stroke patients supports a role for the cortico-spinal pathway in its production or modulation. Monitoring of ShoRe can give insight into the recovery of the descending control of spinal reflexes.

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Changes of Electrically Elicited Reflexes in Hand and Forearm Muscles in Man

Cited by 6 publications

References 14 publications

Short and long latency reflex responses elicited by electrical and mechanical stimulation in human hand muscle

Short and long latency reflex responses elicited by electrical and mechanical stimulation in human hand muscle

Effects of Perturbation Velocity, Direction, Background Muscle Activation, and Task Instruction on Long-Latency Responses Measured From Forearm Muscles

Concurrent changes in shortening reaction latency and reaction time of forearm muscles in post-stroke patients

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