Role of forelimb morphology in muscle sensorimotor functions during locomotion in the cat DOI Creative Commons
Seyed Mohammadali Rahmati, Alexander N. Klishko,

Ramaldo S. Martin

et al.

The Journal of Physiology, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 20, 2024

Abstract Previous studies established strong links between morphological characteristics of mammalian hindlimb muscles and their sensorimotor functions during locomotion. Less is known about the role forelimb morphology in motor outputs generation sensory signals. Here, we measured 46 from six cats. These included muscle attachments, physiological cross‐sectional area (PCSA) fascicle length. We also recorded full‐body mechanics EMG activity level overground treadmill locomotion seven 16 adult cats either sex, respectively. computed forces along with force‐ length‐dependent signals mapped onto corresponding cervical spinal segments. found that patterns afferent activities were strongly affected by muscle's moment arm, PCSA Morphology shoulder suggests distinct roles forelimbs lateral force production movements. Patterns long fibres (brachioradialis, extensor carpi radialis) closely matched overall length, whereas pattern biceps brachii length afferents orientation. conclude cat contributes substantially to locomotor function, particularly control stability turning, rather than propulsion. image Key points Little producing generating somatosensory This information needed understand contributions control. forelimbs, walking electromyographic activity, arms, velocity, activation, muscles, as well length‐ force‐dependent walking. demonstrated contribute proprioceptive regulation cycle phase transitions stability. The obtained can guide development biologically accurate neuromechanical models quadrupedal for exploring testing novel methods treatments central nervous system pathologies modulating neural pathways controlling forelimbs/arms.

Language: Английский

Changes in intra‐ and interlimb reflexes from hindlimb cutaneous afferents after staggered thoracic lateral hemisections during locomotion in cats DOI Creative Commons

Stephen Mari,

Charly G. Lecomte,

Angèle N. Merlet

et al.

The Journal of Physiology, Journal Year: 2024, Volume and Issue: 602(9), P. 1987 - 2017

Published: April 9, 2024

Abstract When the foot dorsum contacts an obstacle during locomotion, cutaneous afferents signal central circuits to coordinate muscle activity in four limbs. Spinal cord injury disrupts these interactions, impairing balance and interlimb coordination. We evoked reflexes by electrically stimulating left right superficial peroneal nerves before after two thoracic lateral hemisections placed on opposite sides of at 9‐ 13‐week interval seven adult cats (4 males 3 females). recorded reflex responses ten hindlimb five forelimb muscles bilaterally. After first (right T5–T6) second (left T10–T11) hemisections, coordination fore‐ hindlimbs was altered and/or became less consistent. hemisection, required assistance perform quadrupedal locomotion. Short‐latency homonymous crossed largely remained unaffected staggered hemisections. However, mid‐ long‐latency both occurred frequently In muscles, homolateral diagonal response occurrence significantly decreased all limbs, however, when present, short‐, maintained their phase‐dependent modulation. also observed reduced durations short‐latency inhibitory extensors early hemisection delayed ipsilesional hemisection. Therefore, changes correlated with impaired balance/stability locomotion spinal injury. Restoring transmission could be used as a biomarker facilitate locomotor recovery. image Key points Cutaneous afferent inputs limbs obstacle. Thoracic communication between centres located cervical lumbar levels, limb investigated nerve bilaterally, cats. showed loss/reduction which balance. Targeting pathways projecting help develop therapeutic approaches aimed restoring ascending descending pathways.

Language: Английский

Citations

15
Forelimb movements contribute to hindlimb cutaneous reflexes during locomotion in cats DOI

Jonathan Harnie,

Rasha Al Arab,

Stephen Mari

et al.

Journal of Neurophysiology, Journal Year: 2024, Volume and Issue: 131(6), P. 997 - 1013

Published: May 1, 2024

During quadrupedal locomotion, interactions between spinal and supraspinal circuits somatosensory feedback coordinate forelimb hindlimb movements. How this is achieved not clear. To determine whether movements modulate cutaneous reflexes involved in responding to an external perturbation, we stimulated the superficial peroneal nerve six intact cats during locomotion hindlimb-only (with forelimbs standing on stationary platform) two with a low transection (T12-T13) locomotion. We compared evoked ipsilateral four contralateral muscles. Results showed similar occurrence phase-dependent modulation of short-latency inhibitory excitatory responses cats. However, depth was reduced semitendinosus Additionally, longer-latency occurred less frequently extensor muscles bilaterally whereas more sartorius anterior, respectively. After transection, were both conditions, mid- or abolished. Our results comparison spinal-transected suggest that absence suppresses inputs from structures and/or cervical cord normally contribute reflex

Language: Английский

Citations

10
A sensory signal related to left-right symmetry modulates intra- and interlimb cutaneous reflexes during locomotion in intact cats DOI Creative Commons

Stephen Mari,

Charly G. Lecomte,

Angèle N. Merlet

et al.

Frontiers in Systems Neuroscience, Journal Year: 2023, Volume and Issue: 17

Published: June 9, 2023

During locomotion, cutaneous reflexes play an essential role in rapidly responding to external perturbation, for example, prevent a fall when the foot contacts obstacle. In cats and humans, involve all four limbs are task- phase modulated generate functionally appropriate whole-body responses.

Language: Английский

Citations

16
Spinal Sensorimotor Circuits Play a Prominent Role in Hindlimb Locomotor Recovery after Staggered Thoracic Lateral Hemisections but Cannot Restore Posture and Interlimb Coordination during Quadrupedal Locomotion in Adult Cats DOI Creative Commons
Johannie Audet, Sirine Yassine,

Charly G. Lecomte

et al.

eNeuro, Journal Year: 2023, Volume and Issue: 10(6), P. ENEURO.0191 - 23.2023

Published: June 1, 2023

Spinal sensorimotor circuits interact with supraspinal and peripheral inputs to generate quadrupedal locomotion. Ascending descending spinal pathways ensure coordination between the forelimbs hindlimbs. cord injury (SCI) disrupts these pathways. To investigate control of interlimb hindlimb locomotor recovery, we performed two lateral thoracic hemisections on opposite sides (right T5-T6 left T10-T11) at an interval approximately months in eight adult cats. In three cats, was transected T12-T13. We collected electromyography (EMG) kinematic data during hindlimb-only locomotion before after lesions. show that (1) cats spontaneously recover following staggered but require balance assistance second one, (2) hindlimbs displays 2:1 patterns (two cycles one forelimb within cycle) becomes weaker more variable both hemisections, (3) left-right asymmetries stance swing durations appear first hemisection reverse second, (4) support periods reorganize favor involving diagonal limbs. Cats expressed day transection, indicating lumbar play a prominent role recovery hemisections. These results reflect series changes allow maintain some level functionality diminished motor commands from brain cervical cord, although posture remains impaired.

Language: Английский

Citations

15
Changes in intra‐ and interlimb reflexes from forelimb cutaneous afferents after staggered thoracic lateral hemisections during locomotion in cats DOI Creative Commons

Stephen Mari,

Charly G. Lecomte,

Angèle N. Merlet

et al.

The Journal of Physiology, Journal Year: 2024, Volume and Issue: 602(22), P. 6225 - 6258

Published: Sept. 27, 2024

Abstract In quadrupeds, such as cats, cutaneous afferents from the forepaw dorsum signal external perturbations and send inputs to spinal circuits co‐ordinate activity in muscles of all four limbs. How these reflex pathways forelimb are reorganized after an incomplete cord injury is not clear. Using a staggered thoracic lateral hemisections paradigm, we investigated changes intralimb interlimb by electrically stimulating left right superficial radial nerves seven adult cats recording responses five ten hindlimb muscles. After first (right T5–T6) second (left T10–T11) hemisections, forelimb–hindlimb co‐ordination was altered weakened. hemisection, required balance assistance perform quadrupedal locomotion. Short‐, mid‐ long‐latency homonymous crossed their phase modulation remained largely unaffected hemisections. The occurrence homolateral diagonal evoked with nerve stimulation significantly reduced at time point but partially recovered stimulation. These were lost or hemisection. When present, responses, including diagonal, maintained phase‐dependent modulation. Therefore, our results show considerable loss transmission cervical lumbar levels injury, albeit preservation modulation, probably affecting functional perturbations. image Key points Cutaneous afferent muscle limbs during locomotion when contacts obstacle. Thoracic disrupts communication between locomotor centres located levels, impairing limb co‐ordination. We reflexes bilaterally, before cats. showed loss/reduction early hemisection that stimulation, being Targeting projecting could help develop therapeutic approaches aimed restoring ascending descending pathways.

Language: Английский

Citations

3
Operation of spinal sensorimotor circuits controlling phase durations during tied-belt and split-belt locomotion after a lateral thoracic hemisection DOI Open Access
Ilya A. Rybak, Natalia A. Shevtsova, Johannie Audet

et al.

Published: Jan. 14, 2025

Locomotion is controlled by spinal circuits that interact with supraspinal drives and sensory feedback from the limbs. These sensorimotor interactions are disrupted following cord injury. The thoracic lateral hemisection represents an experimental model of incomplete injury, where connections between brain abolished on one side cord. To investigate effects such injury operation locomotor network, we used our computational cat locomotion recently published in eLife (Rybak et al., 2024) to predict changes cycle phase durations a during treadmill tied-belt (equal left-right speeds) split-belt (unequal conditions. In simulations, “hemisection” was always applied right side. Based model, hypothesized hemisection, contralesional (“intact”, left) network mostly drives, whereas ipsilesional (“hemisected”, right) somatosensory feedback. We then compared simulated results those obtained experiments adult cats before after mid-thoracic same Our confirmed many predicted simulations. show having hindlimb step slow belt, but not fast substantially reduces hemisection. provides explanations for temporal characteristics based altered circuits,

Language: Английский

Citations

0
Operation of spinal sensorimotor circuits controlling phase durations during tied-belt and split-belt locomotion after a lateral thoracic hemisection DOI Creative Commons
Ilya A. Rybak, Natalia A. Shevtsova, Johannie Audet

et al.

eLife, Journal Year: 2025, Volume and Issue: 13

Published: Jan. 27, 2025

Locomotion is controlled by spinal circuits that interact with supraspinal drives and sensory feedback from the limbs. These sensorimotor interactions are disrupted following cord injury. The thoracic lateral hemisection represents an experimental model of incomplete injury, where connections between brain abolished on one side cord. To investigate effects such injury operation locomotor network, we used our computational cat locomotion recently published in eLife (Rybak et al., 2024) to predict changes cycle phase durations a during treadmill tied-belt (equal left-right speeds) split-belt (unequal conditions. In simulations, ‘hemisection’ was always applied right side. Based model, hypothesized contralesional (‘intact’, left) network mostly drives, whereas ipsilesional (‘hemisected’, right) somatosensory feedback. We then compared simulated results those obtained experiments adult cats before after mid-thoracic same Our confirmed many predicted simulations. show having hindlimb step slow belt, but not fast substantially reduces hemisection. provides explanations for temporal characteristics based altered circuits,

Language: Английский

Citations

0
Spinal sensorimotor circuits play a prominent role in hindlimb locomotor recovery after staggered thoracic lateral hemisections but cannot restore posture and interlimb coordination during quadrupedal locomotion in adult cats DOI Creative Commons
Johannie Audet, Sirine Yassine,

Charly G. Lecomte

et al.

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2023, Volume and Issue: unknown

Published: March 25, 2023

Spinal sensorimotor circuits interact with supraspinal and peripheral inputs to generate quadrupedal locomotion. Ascending descending spinal pathways ensure coordination between the fore-and hindlimbs. cord injury disrupts these pathways. To investigate control of interlimb hindlimb locomotor recovery, we performed two lateral thoracic hemisections placed on opposite sides (right T5-T6 left T10-T11) at an interval approximately months in eight adult cats. In three cats, then made a complete transection caudal second hemisection T12-T13. We collected electromyography kinematic data during hindlimb-only locomotion before after lesions. show that 1) cats spontaneously recover following staggered but require balance assistance one, 2) hindlimbs displays 2:1 patterns becomes weaker more variable both hemisections, 3) left-right asymmetries stance swing durations appear first reverse second, 4) support periods reorganize favor involving forelimbs diagonal limbs. Cats expressed day transection, indicating lumbar play prominent role recovery hemisections. These results reflect series changes allow maintain some level functionality diminished motor commands from brain cervical cord, although posture remains impaired.

Language: Английский

Citations

4
Spinal interneuron population dynamics underlying flexible pattern generation DOI Open Access
Lahiru N. Wimalasena, Chethan Pandarinath, Nicholas Au Yong

et al.

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: June 23, 2024

The mammalian spinal locomotor network is composed of diverse populations interneurons that collectively orchestrate and execute a range behaviors. Despite the identification many classes constituting network, it remains unclear how network's collective activity computes modifies output on step-by-step basis. To investigate this, we analyzed lumbar interneuron population recordings multi-muscle electromyography from spinalized cats performing air stepping used artificial intelligence methods to uncover state space trajectories single step cycles at millisecond timescales. Our analyses revealed traversal specific regions held millisecond-timescale correspondence timing adjustments extensor-flexor alternation. Similarly, found small variations in path were tightly linked single-step, microvolt-scale magnitude muscle output.

Language: Английский

Citations

1
Forelimb movements contribute to hindlimb cutaneous reflexes during locomotion in cats DOI Creative Commons

Jonathan Harnie,

Rasha Al Arab,

Stephen Mari

et al.

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: March 14, 2024

ABSTRACT During quadrupedal locomotion, central circuits interacting with somatosensory feedback coordinate forelimb and hindlimb movements. How this is achieved not clear. To determine if movements modulate cutaneous reflexes involved in responding to an external perturbation, we stimulated the superficial peroneal nerve six intact cats during locomotion hindlimb-only (with forelimbs standing on stationary platform) two spinal-transected locomotion. We compared evoked ipsilateral four contralateral muscles. Results showed similar occurrence phase-dependent modulation of short-latency inhibitory excitatory responses cats. However, depth was reduced semitendinosus Additionally, longer-latency occurred less frequently extensor muscles bilaterally while more sartorius anterior, respectively. After spinal transection, were both conditions, mid- or longer-excitatory abolished. Our results suggest that absence suppresses inputs from supraspinal structures and/or cervical cord normally contribute reflex NEW & NOTEWORTHY coordination involves feedback. demonstrate how movement affects as well show influences reflexes, particularly long-latency responses.

Language: Английский

Citations

1