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Force‐sensitive afferents recruited during stance encode sensory depression in the contralateral swinging limb during locomotion
Author(s) -
Hochman Shawn,
Hayes Heather Brant,
Speigel Iris,
Chang YoungHui
Publication year - 2013
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/nyas.12055
Subject(s) - hindlimb , afferent , sensory system , stimulation , neuroscience , spinal cord , depolarization , anatomy , proprioception , medicine , chemistry , biology , endocrinology
Afferent feedback alters muscle activity during locomotion and must be tightly controlled. As primary afferent depolarization‐induced presynaptic inhibition (PAD‐PSI) regulates afferent signaling, we investigated hindlimb PAD‐PSI during locomotion in an in vitro rat spinal cord–hindlimb preparation. We compared the relation of PAD‐PSI, measured as dorsal root potentials (DRPs), to observed ipsilateral and contralateral limb endpoint forces. Afferents activated during stance‐phase force strongly and proportionately influenced DRP magnitude in the swinging limb. Responses increased with locomotor frequency. Electrical stimulation of contralateral afferents also preferentially evoked DRPs in the opposite limb during swing (flexion). Nerve lesioning, in conjunction with kinematic results, support a prominent contribution from toe Golgi tendon organ afferents. Thus, force‐dependent afferent feedback during stance binds interlimb sensorimotor state to a proportional PAD‐PSI in the swinging limb, presumably to optimize interlimb coordination. These results complement known actions of ipsilateral afferents on PAD‐PSI during locomotion.