scholarly journals On the loop again: understanding human spinal circuitry through the study of its reflex pathway

2019 ◽  
Vol 597 (21) ◽  
pp. 5143-5144 ◽  
Author(s):  
Sidney Grosprêtre
Keyword(s):  
Reflex Pathway ◽  
Spinal Circuitry

Crossed reflex responses to flexor nerve stimulation in mice

2022 ◽  
Author(s):  
Olivier D. Laflamme ◽  
Marwan Ibrahim ◽  
Turgay Akay
Keyword(s):  
Peroneal Nerve ◽  
Muscle Activation ◽  
Mouse Genetics ◽  
Motor Responses ◽  
Reflex Pathway ◽  
Reflex Responses ◽  
Spinal Circuitry ◽  
Extensor Muscles ◽  
Stimulation Of

Motor responses in one leg to sensory stimulation of the contralateral leg have been named "crossed reflexes" and extensively investigated in cats and humans. Despite this effort, a circuit-level understanding of the crossed reflexes has remained missing. In mice, advances in molecular genetics enabled insights into the "commissural spinal circuitry" that ensures coordinated leg movements during locomotion. Despite some common features between the commissural spinal circuitry and the circuit for the crossed reflexes, the degree to which they overlap has remained obscure. Here, we describe excitatory crossed reflex responses elicited by electrically stimulating the common peroneal nerve that mainly innervate ankle flexor muscles and the skin on antero-lateral aspect of the hind leg. Stimulation of the peroneal nerve with low current intensity evoked low amplitude motor responses in the contralateral flexor and extensor muscles. At higher current strengths, stimulation of the same nerve evoked stronger and more synchronous responses in the same contralateral muscles. In addition to the excitatory crossed reflex pathway indicated by muscle activation, we demonstrate the presence of an inhibitory crossed reflex pathway, which was modulated when the motor pools were active during walking. The results are compared with the crossed reflex responses initiated by stimulating proprioceptors from extensor muscles and cutaneous afferents from the posterior part of the leg. We anticipate that these findings will be essential for future research combining the in vivo experiments presented here with mouse genetics to understand crossed reflex pathways at the network level in vivo.

1132: Creation of a Somatic-Autonomic Reflex Pathway for Treatment of Neurogenic Bladder in Patients with Spinal Cord Injury: Preliminary Results of First 2 USA Patients

2005 ◽  
Vol 173 (4S) ◽  
pp. 307-308 ◽  
Author(s):  
Christopher E. Kelly ◽  
Chuan-Guo Xiao ◽  
Howard Weiner ◽  
Aleksandar Beric ◽  
Victor W. Nitti ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Neurogenic Bladder ◽  
Reflex Pathway ◽  
Preliminary Results ◽  
Cord Injury ◽  
Autonomic Reflex

scholarly journals Modulation of torque evoked by wide-pulse, high-frequency neuromuscular electrical stimulation and the potential implications for rehabilitation and training

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chris Donnelly ◽  
Jonathan Stegmüller ◽  
Anthony J. Blazevich ◽  
Fabienne Crettaz von Roten ◽  
Bengt Kayser ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
High Frequency ◽  
Neuromuscular Electrical Stimulation ◽  
Motor Units ◽  
Progressive Increase ◽  
Great Promise ◽  
Measured Parameter ◽  
Time Integral ◽  
Spinal Circuitry ◽  
Evoked Force

AbstractThe effectiveness of neuromuscular electrical stimulation (NMES) for rehabilitation is proportional to the evoked torque. The progressive increase in torque (extra torque) that may develop in response to low intensity wide-pulse high-frequency (WPHF) NMES holds great promise for rehabilitation as it overcomes the main limitation of NMES, namely discomfort. WPHF NMES extra torque is thought to result from reflexively recruited motor units at the spinal level. However, whether WPHF NMES evoked force can be modulated is unknown. Therefore, we examined the effect of two interventions known to change the state of spinal circuitry in opposite ways on evoked torque and motor unit recruitment by WPHF NMES. The interventions were high-frequency transcutaneous electrical nerve stimulation (TENS) and anodal transcutaneous spinal direct current stimulation (tsDCS). We show that TENS performed before a bout of WPHF NMES results in lower evoked torque (median change in torque time-integral: − 56%) indicating that WPHF NMES-evoked torque might be modulated. In contrast, the anodal tsDCS protocol used had no effect on any measured parameter. Our results demonstrate that WPHF NMES extra torque can be modulated and although the TENS intervention blunted extra torque production, the finding that central contribution to WPHF NMES-evoked torques can be modulated opens new avenues for designing interventions to enhance WPHF NMES.

scholarly journals Presynaptic inhibition of the monosynaptic reflex pathway in kittens

1963 ◽  
Vol 165 (3) ◽  
pp. 403-420 ◽  
Author(s):  
Rosamond M. Eccles ◽  
W. D. Willis
Keyword(s):  
Presynaptic Inhibition ◽  
Monosynaptic Reflex ◽  
Reflex Pathway

5‐Hydroxytryptamine contributes significantly to a reflex pathway by which the duodenal mucosa protects itself from gastric acid injury

2006 ◽  
Vol 20 (14) ◽  
pp. 2486-2495 ◽  
Author(s):  
Anders J. Smith ◽  
Alfred E. Chappell ◽  
Andre G. Buret ◽  
Kim E. Barrett ◽  
Hui Dong
Keyword(s):  
Gastric Acid ◽  
Duodenal Mucosa ◽  
Reflex Pathway

scholarly journals Backward walking highlights gait asymmetries in children with cerebral palsy

2018 ◽  
Vol 119 (3) ◽  
pp. 1153-1165 ◽  
Author(s):  
Germana Cappellini ◽  
Francesca Sylos-Labini ◽  
Michael J. MacLellan ◽  
Annalisa Sacco ◽  
Daniela Morelli ◽  
...  
Keyword(s):  
Cerebral Palsy ◽  
Muscle Activation ◽  
Pattern Generation ◽  
Comprehensive Assessment ◽  
Emg Activity ◽  
Backward Walking ◽  
Spinal Circuitry ◽  
Children With Cerebral Palsy ◽  
Control Circuits ◽  
The Brain

To investigate how early injuries to developing motor regions of the brain affect different forms of gait, we compared the spatiotemporal locomotor patterns during forward (FW) and backward (BW) walking in children with cerebral palsy (CP). Bilateral gait kinematics and EMG activity of 11 pairs of leg muscles were recorded in 14 children with CP (9 diplegic, 5 hemiplegic; 3.0–11.1 yr) and 14 typically developing (TD) children (3.3–11.8 yr). During BW, children with CP showed a significant increase of gait asymmetry in foot trajectory characteristics and limb intersegmental coordination. Furthermore, gait asymmetries, which were not evident during FW in diplegic children, became evident during BW. Factorization of the EMG signals revealed a comparable structure of the motor output during FW and BW in all groups of children, but we found differences in the basic temporal activation patterns. Overall, the results are consistent with the idea that both forms of gait share pattern generation control circuits providing similar (though reversed) kinematic patterns. However, BW requires different muscle activation timings associated with muscle modules, highlighting subtle gait asymmetries in diplegic children, and thus provides a more comprehensive assessment of gait pathology in children with CP. The findings suggest that spatiotemporal asymmetry assessments during BW might reflect an impaired state and/or descending control of the spinal locomotor circuitry and can be used for diagnostic purposes and as complementary markers of gait recovery.NEW & NOTEWORTHY Early injuries to developing motor regions of the brain affect both forward progression and other forms of gait. In particular, backward walking highlights prominent gait asymmetries in children with hemiplegia and diplegia from cerebral palsy and can give a more comprehensive assessment of gait pathology. The observed spatiotemporal asymmetry assessments may reflect both impaired supraspinal control and impaired state of the spinal circuitry.

scholarly journals Time-dependent modulation of spinal excitability during action observation in the macaque monkey

2019 ◽  
Author(s):  
S.J. Jerjian ◽  
R.N. Lemon ◽  
A. Kraskov
Keyword(s):  
Pyramidal Tract ◽  
Rhesus Macaques ◽  
Action Observation ◽  
Macaque Monkey ◽  
Reach To Grasp ◽  
Hand Muscles ◽  
Spinal Circuitry ◽  
Hand Muscle ◽  
Spinal Excitability ◽  
Muscle Responses

ABSTRACTNeurons in the primate motor cortex, including identified pyramidal tract neurons projecting to the spinal cord, respond to the observation of others’ actions, yet this does not cause movement in the observer. Here, we investigated changes in spinal excitability during action observation by monitoring short latency electromyographic responses produced by single shocks delivered directly to the pyramidal tract. Responses in hand and digit muscles were recorded from two adult rhesus macaques while they performed, observed or withheld reach-to-grasp and hold actions. We found modest grasp-specific facilitation of hand muscle responses during hand shaping for grasp, which persisted when the grasp was predictable but obscured from the monkey’s vision. We also found evidence of a more general inhibition before observed movement onset, and the size of this inhibition effect was comparable to the inhibition after an explicit NoGo signal. These results confirm that the spinal circuitry controlling hand muscles is modulated during action observation, and this may be driven by internal representations of actions. The relatively modest changes in spinal excitability during observation suggest net corticospinal outflow exerts only minor, sub-threshold changes on hand motoneuron pools, thereby preventing any overflow of mirror activity into overt movement.

The pupillary light reflex pathway: Cytoarchitectonic probabilistic maps in hemianopic patients

Neurology ◽  
2008 ◽  
Vol 70 (12) ◽  
pp. 956-963 ◽  
Author(s):  
E. Papageorgiou ◽  
L. F. Ticini ◽  
G. Hardiess ◽  
F. Schaeffel ◽  
H. Wiethoelter ◽  
...  
Keyword(s):  
Pupillary Light Reflex ◽  
Reflex Pathway ◽  
Light Reflex ◽  
Pupillary Light ◽  
Probabilistic Maps
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