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Updated: Oct 28, 2026

An In Vitro Adult Mouse Muscle-nerve Preparation for Studying the Firing Properties of Muscle Afferents
Published on: September 24, 2014
Coupling between single muscle spindle afferent and EMG in human wrist extensor muscles: physiological evidence of
1Department of Neurology, National Rehabilitation Center for the Disabled, Tokorozawa, Saitama, Japan. J90016@simail.ne.jp
Objectives:
This study was conducted to find physiological evidence of skeletofusimotor innervation in man.
Methods:
Discharges of 38 single muscle spindle afferents from m. extensor carpi radialis were recorded from 9 subjects during steady isometric contractions of wrist extension. Correlation between these afferents and rectified surface EMG was investigated by estimating cumulant density function.
Results:
In the cumulant density estimate between spindle afferent and EMG, a positive EMG peak was obtained prior to afferent firing between -30 and -10 ms in 15 afferents (39%).
Conclusions:
The present finding indicates coupling between spindle afferents and extrafusal activity and suggests the widespread skeletofusimotor innervation in human muscle spindle.
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