Spinal cord maps of spatiotemporal alpha-motoneuron activation in humans walking at different speeds. J Neurophysiol 95: 602-618, 2006. First published November 9, 2005; doi: 10.1152/jn. 00767.2005. Functional MRI (fMRI) imaging of motoneuron activity in the human spinal cord is still in its infancy, and it will remain difficult to apply to walking. Here we present a viable alternative for documenting the spatiotemporal maps of alpha-motorneuron (MN) activity in the human spinal cord during walking, similar to the method recently reported for the cat. We recorded EMG activity from 16 to 32 ipsilateral limb and trunk muscles in 13 healthy subjects walking on a treadmill at different speeds (1-7 km/h) and mapped the recorded patterns onto the spinal cord in approximate rostrocaudal locations of the motoneuron pools. This approach can provide information about pattern generator output during locomotion in terms of segmental control rather than in terms of individual muscle control. A striking feature we found is that nearly every spinal segment undergoes at least two cycles of activation in the step cycle, thus supporting the idea of half-center oscillators controlling MN activation at any segmental level. The resulting spatiotemporal map patterns seem highly stereotyped over the range of walking speeds studied, although there were also some systematic redistributions of MN activity with speed. Bursts of MN activity were either temporally aligned across several spinal segments or switched between different segments. For example, the center of mass of MN activity in the lumbosacral levels generally shifted from rostral to caudal positions in two cycles for each step, revealing four major activation foci: two in the upper lumbar segments and two in the sacral segments. The results are consistent with the presence of at least two and possibly more pattern generators controlling the activation of lumbosacral MNs.

Ivanenko, Y.p., Poppele, R.e., Lacquaniti, F. (2006). Spinal cord maps of spatiotemporal alpha-motoneuron activation in humans walking at different speeds. JOURNAL OF NEUROPHYSIOLOGY, 95(2), 602-618 [10.1152/jn.00767.2005].

Spinal cord maps of spatiotemporal alpha-motoneuron activation in humans walking at different speeds

LACQUANITI, FRANCESCO
2006-01-01

Abstract

Spinal cord maps of spatiotemporal alpha-motoneuron activation in humans walking at different speeds. J Neurophysiol 95: 602-618, 2006. First published November 9, 2005; doi: 10.1152/jn. 00767.2005. Functional MRI (fMRI) imaging of motoneuron activity in the human spinal cord is still in its infancy, and it will remain difficult to apply to walking. Here we present a viable alternative for documenting the spatiotemporal maps of alpha-motorneuron (MN) activity in the human spinal cord during walking, similar to the method recently reported for the cat. We recorded EMG activity from 16 to 32 ipsilateral limb and trunk muscles in 13 healthy subjects walking on a treadmill at different speeds (1-7 km/h) and mapped the recorded patterns onto the spinal cord in approximate rostrocaudal locations of the motoneuron pools. This approach can provide information about pattern generator output during locomotion in terms of segmental control rather than in terms of individual muscle control. A striking feature we found is that nearly every spinal segment undergoes at least two cycles of activation in the step cycle, thus supporting the idea of half-center oscillators controlling MN activation at any segmental level. The resulting spatiotemporal map patterns seem highly stereotyped over the range of walking speeds studied, although there were also some systematic redistributions of MN activity with speed. Bursts of MN activity were either temporally aligned across several spinal segments or switched between different segments. For example, the center of mass of MN activity in the lumbosacral levels generally shifted from rostral to caudal positions in two cycles for each step, revealing four major activation foci: two in the upper lumbar segments and two in the sacral segments. The results are consistent with the presence of at least two and possibly more pattern generators controlling the activation of lumbosacral MNs.
2006
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore BIO/09 - FISIOLOGIA
English
adult; aged; alpha nerve fiber; article; electromyogram; female; functional magnetic resonance imaging; human; human experiment; locomotion; male; muscle contraction; nerve conduction; priority journal; spinal cord; walking speed; action potential; biological rhythm; body equilibrium; electromyography; exercise; gait; innervation; motoneuron; physiology; skeletal muscle; walking; Action Potentials; Adult; Biological Clocks; Electromyography; Exertion; Female; Gait; Humans; Male; Motor Neurons; Muscle Contraction; Muscle, Skeletal; Musculoskeletal Equilibrium; Spinal Cord; Walking
Ivanenko, Y.p., Poppele, R.e., Lacquaniti, F. (2006). Spinal cord maps of spatiotemporal alpha-motoneuron activation in humans walking at different speeds. JOURNAL OF NEUROPHYSIOLOGY, 95(2), 602-618 [10.1152/jn.00767.2005].
Ivanenko, Yp; Poppele, Re; Lacquaniti, F
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/35054
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