Crossed reflex reversal during human locomotion

2013 ◽  
Vol 109 (9) ◽  
pp. 2335-2344 ◽  
Author(s):  
Sabata Gervasio ◽  
Dario Farina ◽  
Thomas Sinkjær ◽  
Natalie Mrachacz-Kersting
Keyword(s):  
Sural Nerve ◽  
Tibial Nerve ◽  
Human Locomotion ◽  
Muscle Afferents ◽  
Short Latency ◽  
Heel Strike ◽  
Contralateral Limb ◽  
Reflex Reversal ◽  
Synergistic Muscles ◽  
Gastrocnemius Lateralis

During human walking, precise coordination between the two legs is required in order to react promptly to any sudden hazard that could threaten stability. The networks involved in this coordination are not yet completely known, but a direct spinal connection between soleus (SOL) muscles has recently been revealed. For this response to be functional, as previously suggested, we hypothesize that it will be accompanied by a reaction in synergistic muscles, such as gastrocnemius lateralis (GL), and that a reversal of the response would occur when an opposite reaction is required. In the present study, surface EMGs of contralateral SOL and GL were analyzed after tibial nerve (TN), sural nerve (SuN), and medial plantar nerve (MpN) stimulation during two tasks in which opposite reactions are functionally expected: normal walking (NW), just before ipsilateral heel strike, and hybrid walking (HW) (legs walking in opposite directions), at ipsilateral push off and contralateral touchdown. Early crossed facilitations were observed in the contralateral GL after TN stimulation during NW, and a reversal of such responses occurred during HW. These results underline the functional significance of short-latency crossed responses and represent the first evidence for short-latency reflex reversal in the contralateral limb for humans. Muscle afferents seem to mediate the response during NW, while during HW cutaneous afferents are likely involved. It is thus possible that different afferents mediate the crossed response during different tasks.

scholarly journals A Comparison of Interside Asymmetries of Lower Extremity Somatosensory Evoked Potentials in Anesthetized Patients with Unilateral Lumbosacral Radiculopathy

2017 ◽  
Vol 11 (1) ◽  
pp. 99-104
Author(s):  
Qing Yue ◽  
Tyson Hale ◽  
Aaron Knecht
Keyword(s):  
Lower Extremity ◽  
Evoked Potentials ◽  
Somatosensory Evoked Potentials ◽  
Sural Nerve ◽  
Tibial Nerve ◽  
Control Group ◽  
Superficial Peroneal Nerve ◽  
Asymmetry Ratio ◽  
Lumbosacral Radiculopathy ◽  
Posterior Tibial

<sec><title>Study Design</title><p>Prospective cohort study.</p></sec><sec><title>Purpose</title><p>This study was to investigate interside asymmetries of three lower extremity somatosensory evoked potentials (SSEPs) in anesthetized patients with unilateral lumbosacral radiculopathy.</p></sec><sec><title>Overview of Literature</title><p>Although interside asymmetry is an established criterion of abnormal SSEP, little is known which of the lower SSEPs is more sensitive in detecting interside asymmetry in anesthetized patients.</p></sec><sec><title>Methods</title><p>Superficial peroneal nerve SSEP (SPN-SSEP), posterior tibial nerve SSEP (PTN-SSEP), and sural nerve SSEP were obtained in 31 lumbosacral surgery patients with unilateral lumbosacral radiculopathy, and compared with a group of 22 control subjects.</p></sec><sec><title>Results</title><p>The lumbosacral group showed significant larger interside asymmetry ratios of P37 latencies in SPN-SSEP and PTN-SSEP, and significant larger interside asymmetry ratio of P37-N45 amplitude in SPN-SSEP, when comparing with the control group. Within the lumbosacral group but not the control group, SPN-SSEP displayed significant larger interside asymmetry ratio in P37 latency. When referencing to the control group, more patients in the lumbosacral group displayed abnormal interside SPN-SSEP latency asymmetrieswhich corroborated the symptom laterality.</p></sec><sec><title>Conclusions</title><p>The data suggested that SPN-SSEP was more sensitive in detecting interside latency asymmetry in anesthetized patients.</p></sec>

Short-Latency Crossed Inhibitory Responses in the Human Soleus Muscle

2009 ◽  
Vol 102 (6) ◽  
pp. 3596-3605 ◽  
Author(s):  
Peter W. Stubbs ◽  
Natalie Mrachacz-Kersting
Keyword(s):  
Electrical Stimulation ◽  
Nerve Stimulation ◽  
Muscle Activation ◽  
Tibial Nerve ◽  
Voluntary Contraction ◽  
Short Latency ◽  
Afferent Feedback ◽  
Medial Plantar Nerve ◽  
Muscle Activation Patterns ◽  
Tibial Nerve Stimulation

Even though interlimb coordination is critical in bipedal locomotion, the role of muscle afferent mediated feedback is unknown. The aim of this study was to establish if ipsilateral muscle generated afferent feedback can influence contralateral muscle activation patterns in the human lower limb and to elucidate the mechanisms involved. The effect of ipsilateral tibial nerve stimulation on contralateral soleus (cSOL) responses were quantified. Three interventions were investigated, 1) electrical stimulation applied to the tibial nerve at stimulation intensities from 0 to 100% of maximal M-wave (M-max) with the cSOL contracted from 5 to 15% of maximal voluntary contraction (MVC) and 15 to 30% MVC, 2) ispsilateral tibial nerve stimulation at 75% M-max prior to, during, and following the application of ischemia to the ipsilateral thigh. 3) Electrical stimulation applied to the ipsilateral sural (SuN) and medial plantar nerves at stimulation intensities from 1 to 3 times perceptual threshold. A short-latency depression in the cSOL electromyogram (EMG; onset: 37–41 ms) was observed following ipsilateral tibial nerve stimulation. The magnitude of this depression increased ( P = 0.0005 and P = 0.000001) with increasing stimulus intensities. Ischemia delayed the time of the minimum of the cSOL depression ( P = 0.04). SuN and medial plantar nerve stimulation evoked a longer latency depression [average; 91.2 ms (SuN); 142 ms (medial plantar nerve)] and therefore do not contribute to the response. This is the first study to demonstrate a short-latency depression in the cSOL following ipsilateral tibial nerve stimulation. Due to its short latency, the response is spinally mediated. The involvement of crossed spinal interneurons receiving input from low-threshold muscle afferents is discussed.

Factors determining segmental reflex action in normal and decerebrate cats

1990 ◽  
Vol 64 (5) ◽  
pp. 1625-1635 ◽  
Author(s):  
T. Sinkjaer ◽  
J. A. Hoffer
Keyword(s):  
Muscle Length ◽  
Muscle Spindles ◽  
Radiant Heat ◽  
Companion Paper ◽  
Muscle Afferents ◽  
Short Latency ◽  
Lateral Gastrocnemius ◽  
Implanted Electrodes ◽  
Extensor Muscles ◽  
Before And After

1. In the companion paper the gain of the stretch reflex in the ankle extensor muscles of normal cats was shown to increase after decerebration. The objectives of this study were 1) to identify the origin of the increased reflex and 2) to evaluate the contribution from afferents other than ankle extensor muscle afferents to the short-latency reflex. 2. Six cats were trained to stand unaided on four pedestals. Three cats were also trained to control the force exerted with the left hindlimb. The left soleus (SOL) and lateral gastrocnemius (LG) electromyogram (EMG), length, force, and temperature were recorded by chronically implanted electrodes and transducers. Measurements were taken before and after decerebration at the premammillary level. After decerebration limb temperature was returned to its normal range by the use of radiant heat. 3. Reproducible ramp-and-hold stretches and releases of the ankle extensor muscles were produced by a servo-controlled motor that rotated the left rear pedestal about the ankle joint. The length of the ankle extensor muscles changed by 2-3 mm within 30-35 ms after the onset of a ramp perturbation. Reflex responses before and after decerebration were compared at matched background values of muscle length and force. 4. In both the SOL and LG muscles, a short-latency EMG burst appeared 8-12 ms after stretch onset and lasted approximately 20 ms. After decerebration the onset of the rectified and smoothed EMG burst remained unchanged, but its area was increased by 36-89%. 5. The lateral gastrocnemius-soleus (LG-S) electroneurogram (ENG) was chronically recorded in two cats with a nerve cuff recording electrode implanted on the LG-S nerve. LG-S ENG activity started to increase soon after stretch onset and remained high during the entire ramp phase. The stretch-evoked LG-S ENG burst started approximately 8 ms earlier than the short-latency SOL and LG EMG bursts. It was interpreted to reflect mainly an increase in the activity of Group Ia and Ib muscle afferents, caused by increases in both muscle length and muscle force during the stretch. After the cats were decerebrated, for matched postural conditions, the area of the stretch-evoked LG-S ENG burst was increased by 29-35%. Because the length and force changes sensed by the muscle receptors before and after decerebration were similar, this suggests that the sensitivity of muscle spindles was increased as a consequence of altered activity in fusimotor neurons after decerebration.(ABSTRACT TRUNCATED AT 400 WORDS)

Arm cycling increases short-latency reflex from ankle dorsiflexor afferents to knee extensor muscles

2020 ◽  
Author(s):  
Syusaku SASADA ◽  
Toshiki Tazoe ◽  
Tsuyoshi Nakajima ◽  
Shigeki Omori ◽  
Genki Futatsubashi ◽  
...  
Keyword(s):  
Isometric Contraction ◽  
Knee Extensor ◽  
Short Latency ◽  
Reflex Response ◽  
Heel Strike ◽  
Reflex Modulation ◽  
Arm Cycling ◽  
Extensor Muscles ◽  
Neural Coupling ◽  
Knee Extensor Muscles

Low-intensity electrical stimulation of the common peroneal nerve (CPN) evokes a short latency reflex in the heteronymous knee extensor muscles (referred to as CPN-reflex). The CPN-reflex is facilitated at a heel strike during walking, contributing to body weight support. However, the origin of the CPN-reflex increase during walking remains unclear. We speculate that this increase originates from multiple sources due to a body of evidence suggesting the presence of neural coupling between the arms and legs. Therefore, we investigated the extent to which the CPN-reflex is modulated during rhythmic arm cycling. Twenty-eight subjects sat in an armchair and were asked to perform arm cycling at a moderate cadence using a stationary ergometer while performing isometric contraction of the knee extensors, such that the CPN-reflex was evoked. CPN-reflex was evoked by stimulating the CPN (0.9-2.0 × the motor threshold [MT] in the tibialis anterior muscle) at the level of the neck of the fibula. The CPN-reflex amplitude was measured from the vastus lateralis (VL). The biphasic reflex response in the VL was evoked within 27-45 ms following CPN stimulation. The amplitude of the CPN-reflex increased during arm cycling compared with that before cycling. The modulation of the CPN-reflex during arm cycling was detected only for CPN stimulation intensity around 1.2 × MT. Furthermore, CPN-reflex modulation was not observed during the isometric contraction of the arm or passive arm cycling. Our results suggest the presence of neural coupling between the CPN-reflex pathways and neural systems generating locomotive arm movement.

scholarly journals Lower limb kinematic, kinetic, and EMG data from young healthy humans during walking at controlled speeds

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Luís Moreira ◽  
Joana Figueiredo ◽  
Pedro Fonseca ◽  
João P. Vilas-Boas ◽  
Cristina P. Santos
Keyword(s):  
Lower Limb ◽  
Vastus Lateralis ◽  
Force Plate ◽  
Biceps Femoris ◽  
Human Locomotion ◽  
Reference Trajectory ◽  
Healthy Humans ◽  
Complete Dataset ◽  
Reaction Forces ◽  
Gastrocnemius Lateralis

AbstractUnderstanding the lower limb kinematic, kinetic, and electromyography (EMG) data interrelation in controlled speeds is challenging for fully assessing human locomotion conditions. This paper provides a complete dataset with the above-mentioned raw and processed data simultaneously recorded for sixteen healthy participants walking on a 10 meter-flat surface at seven controlled speeds (1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 km/h). The raw data include 3D joint trajectories of 24 retro-reflective markers, ground reaction forces (GRF), force plate moments, center of pressures, and EMG signals from Tibialis Anterior, Gastrocnemius Lateralis, Biceps Femoris, and Vastus Lateralis. The processed data present gait cycle-normalized data including filtered EMG signals and their envelope, 3D GRF, joint angles, and torques. This study details the experimental setup and presents a brief validation of the data quality. The presented dataset may contribute to (i) validate and enhance human biomechanical gait models, and (ii) serve as a reference trajectory for personalized control of robotic assistive devices, aiming an adequate assistance level adjusted to the gait speed and user’s anthropometry.

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