TY - JOUR

T1 - Functional Organization of the Spinal Locomotor Network Based on Analysis of Interneuronal Activity

AU - Musienko, P

AU - Gorskii, O

AU - Deliagina, T

AU - Zelenin, P

N1 - Times Cited in Web of Science Core Collection: 0 Total Times Cited: 0 Cited Reference Count: 65

PY - 2025

Y1 - 2025

N2 - Locomotion is a vital motor function for any living being. In vertebrates, a basic locomotor pattern is controlled by the spinal locomotor network (SLN). Although SLN has been extensively studied, due to technical difficulties, most data were obtained during fictive locomotion, and data about the activity of spinal neurons during locomotion with intact sensory feedback from limbs are extremely limited. Here, we overcame the technical problems and recorded the activity of putative spinal interneurons from spinal segments L4-L6 during treadmill forward locomotion evoked by stimulation of the mesencephalic locomotor region in the decerebrate cat. We found that neurons were activated and inactivated preferably within one of the four phase ranges presumably related to preparation for the limb lift-off, the limb lift-off, transition from the limb flexion to limb extension during swing, and the limb touch-down. We analyzed the activity phases of recorded interneurons by using a new method that took into account the previously ignored information about the stability of neuronal modulation in the sequential locomotor cycles. We suggested that neurons with stable modulation (i.e., small dispersion of their activity phase in sequential cycles) represent the core of SLN. Our analysis revealed groups of neurons active approximately out of phase and presumably contributing to the control of vertical (VC) and horizontal (HC) components of the step. We found that most VC- and HC-related neurons were located in the intermediate and dorsal/ventral parts of the grey matter, respectively. Our experimental data can be used as a benchmark for computational models of locomotor neuronal networks.

AB - Locomotion is a vital motor function for any living being. In vertebrates, a basic locomotor pattern is controlled by the spinal locomotor network (SLN). Although SLN has been extensively studied, due to technical difficulties, most data were obtained during fictive locomotion, and data about the activity of spinal neurons during locomotion with intact sensory feedback from limbs are extremely limited. Here, we overcame the technical problems and recorded the activity of putative spinal interneurons from spinal segments L4-L6 during treadmill forward locomotion evoked by stimulation of the mesencephalic locomotor region in the decerebrate cat. We found that neurons were activated and inactivated preferably within one of the four phase ranges presumably related to preparation for the limb lift-off, the limb lift-off, transition from the limb flexion to limb extension during swing, and the limb touch-down. We analyzed the activity phases of recorded interneurons by using a new method that took into account the previously ignored information about the stability of neuronal modulation in the sequential locomotor cycles. We suggested that neurons with stable modulation (i.e., small dispersion of their activity phase in sequential cycles) represent the core of SLN. Our analysis revealed groups of neurons active approximately out of phase and presumably contributing to the control of vertical (VC) and horizontal (HC) components of the step. We found that most VC- and HC-related neurons were located in the intermediate and dorsal/ventral parts of the grey matter, respectively. Our experimental data can be used as a benchmark for computational models of locomotor neuronal networks.

KW - decerebrate cat

KW - locomotion

KW - mesencephalic locomotor region

KW - neuronal network

KW - spinal cord

KW - spinal neurons

KW - CENTRAL PATTERN GENERATOR

KW - LEFT-RIGHT COORDINATION

KW - FICTIVE LOCOMOTION

KW - NEURONAL-ACTIVITY

KW - MUSCLE SYNERGIES

KW - V2A INTERNEURONS

KW - RENSHAW CELLS

KW - BRAIN-STEM

KW - CAT

KW - PHASE

U2 - 10.1111/ejn.70238

DO - 10.1111/ejn.70238

M3 - Article

VL - 62

JO - European Journal of Neuroscience

JF - European Journal of Neuroscience

SN - 0953-816X

IS - 4

ER -