Task dependence of Ia presynaptic inhibition in human wrist extensor muscles: a single motor unit study

Aimonetti, Jean Marc; Vedel, Jean‐Pierre; Schmied, Annie; Pagni, Simone

doi:10.1016/s1388-2457(00)00293-5

Cited by 15 publications

(5 citation statements)

References 34 publications

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“…When the issue of task specificity has been addressed in the upper limb, it has often been in the context of reflex modulation by change in the type or intent of contraction (e.g. co‐contraction) (Aimonetti et al 1999, 2000). Additionally, some evidence also suggests that stretch reflexes in the upper limb may be differentially modulated depending upon the intent of the subjects during a sinusoidal tracking task (Dietz et al 1994).…”

Section: Discussionmentioning

confidence: 99%

Neural control of rhythmic, cyclical human arm movement: task dependency, nerve specificity and phase modulation of cutaneous reflexes

Zehr

Kido

2001

J Physiology

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Section: Discussionmentioning

confidence: 99%

Neural control of rhythmic, cyclical human arm movement: task dependency, nerve specificity and phase modulation of cutaneous reflexes

Zehr

Kido

2001

J Physiology

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“…10, 71, 97). A major control mechanism involved in the fine-tuning of afferent feedback is the modulation of Ia presynaptic inhibition (PSI), particularly during locomotor tasks for the leg (10,13,22) and in the wrist during arm movements (3)(4)(5)63). Significant modulation (inhibition) of the soleus H-reflex amplitude occurs when changing posture from lying, to sitting, to standing (6,36,44,45,54,56).…”

Section: Acute Plasticity: Short-term Adjustments Of Reflexes To Postmentioning

confidence: 99%

Training-induced adaptive plasticity in human somatosensory reflex pathways

Zehr¹

2006

Journal of Applied Physiology

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This paper reviews evidence supporting adaptive plasticity in muscle and cutaneous afferent reflex pathways induced by training and rehabilitative interventions. The perspective is advanced that the behavioral and functional relevance of any intervention and the reflex pathway under study should be considered when evaluating both adaptation and transfer. A cornerstone of this concept can be found in acute task-dependent reflex modulation. Because the nervous system allows the expression of a given reflex according to the motor task, an attempt to evaluate the training adaptation should also be evoked under the same conditions as training bearing in mind the functional role of the pathway under study. Within this framework, considerable evidence supports extensive adaptive plasticity in human muscle afferent pathways in the form of operant conditioning, strength training, skill training, and locomotor training or retraining. Directly comparable evidence for chronic adaptation in cutaneous reflex pathways is lacking. However, activity-dependent plasticity in cutaneous pathways is documented particularly in approaches to neurological rehabilitation. Overall, the adaptive range for human muscle afferent reflexes appears bidirectional (that is, increased or reduced amplitudes) and on the order of 25-50%. The adaptive range for cutaneous pathways is currently uncertain.

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“…Task-dependent modulation is manifested with changes in posture from lying to standing, from standing to walking and from walking to running, which causes a progressive decline in soleus H-reflex excitability (Angulo-Kinzler et al, 1998;Capaday and Stein, 1986;Crenna and Frigo, 1987;Koceja et al, 1995Koceja et al, , 1993Mynark and Koceja, 1997;. The decrease in H-reflex excitability results from increases in Ia presynaptic inhibition and has been shown during rhythmic leg Capaday and Stein, 1986;Crenna and Frigo, 1987) , arm ) and wrist movements (Aimonetti et al, 2000a(Aimonetti et al, , 2000b(Aimonetti et al, , 1999Brooke et al, 2000). Similarly, cutaneous reflexes are altered when compared between standing and walking or running .…”

Section: Reflexes As a Probe To Understand The Neural Control Of Rhyt...mentioning

confidence: 99%

Exploiting evolutionarily conserved pathways to promote plasticity of human spinal circuits

Pearcey

2020

Appl. Physiol. Nutr. Metab.

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Humans evolved from species that walked on all 4 limbs, which means that experiments in quadrupeds can guide and support experiments in humans. This is particularly helpful for neural rehabilitation because the central nervous system is plastic in nature, meaning that activities promoting central nervous system activity can alter subsequent output properties. This is known as neuroplasticity and can be measured as changes in spinal cord excitability through reflexes as a proxy. By targeting evolutionarily conserved pathways that act on similar interneurons within the spinal cord to either increase or decrease excitability, it may be possible to preferentially modulate spinal cord excitability based on a desirable outcome. For example, rhythmic movement reduces spinal cord excitability whereas brief sensory input to cutaneous afferents increases spinal cord excitability. Alterations in spinal cord excitability have been shown to outlast the activity duration, suggesting that neuroplasticity is not transient. This evidence suggests that both rhythmic movement and sensory input can induce acute neuroplasticity of spinal cord excitability. The overall purpose of this dissertation was 2-fold: (i) to provide reviews of how evolutionarily conserved pathways are studied in humans and how they contribute to human rhythmic movement; and (ii) experimentally examine how these conserved pathways, which converge onto similar interneuron circuitry, can be exploited to cause bidirectional changes in spinal cord excitability. Reviews indicate that humans have retained characteristics of quadrupedal locomotion and, in particular, activity of the arms affects the excitability of the legs, and vice versa. Cutaneous input is integrated throughout the body during locomotion, such that cutaneous sensations elicit neuromechanical responses that are nerve-specific and modulated according to the phase of movement. In experiment 1, there was increased spinal cord excitability following patterned stimulation of cutaneous afferents innervating the bottom of the foot. In experiment 2, stimulation to cutaneous afferents innervating both the top and bottom of the foot amplified voluntary plantar- and dorsiflexion. In experiment 3, cervicolumbar connections were exploited to amplify plasticity in spinal cord excitability induced by rhythmic movement. Finally, in experiment 4, there were interactions of rhythmic movement and fatigue, which both reduce spinal cord excitability, with cutaneous stimulation, which increases spinal cord excitability, such that reductions in spinal cord excitability associated with fatigue were mitigated by cutaneous stimulation. Taken together, these experiments suggest that cutaneous stimulation can increase spinal cord excitability, whereas quadrupedal locomotor activity can decrease spinal cord excitability. These conserved pathways can be exploited to intentionally modify spinal cord excitability in a bidirectional fashion, which provides fruitful information for the exploration of rehabilitation and sport performance practices.

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Task dependence of Ia presynaptic inhibition in human wrist extensor muscles: a single motor unit study

Cited by 15 publications

References 34 publications

Neural control of rhythmic, cyclical human arm movement: task dependency, nerve specificity and phase modulation of cutaneous reflexes

Neural control of rhythmic, cyclical human arm movement: task dependency, nerve specificity and phase modulation of cutaneous reflexes

Training-induced adaptive plasticity in human somatosensory reflex pathways

Exploiting evolutionarily conserved pathways to promote plasticity of human spinal circuits

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