Automatic Postural Responses Are Delayed by Pyridoxine-Induced Somatosensory Loss

• DOI: 10.1523/jneurosci.22-14-05803.2002
• Publication Date: 2018-04-03T19:25:25Z
• Authors: Paul J. Stapley; Lena H. Ting; Manuel Hulliger; Jane M. Macpherson
• Keywords: Hindlimb; Scratching

Pyridoxine given in large doses is thought to destroy selectively the large-diameter peripheral sensory nerve fibers, leaving motor fibers intact. This study examined effects of pyridoxine-induced somatosensory loss on automatic postural responses sudden displacements support surface standing cat. Two cats were trained stand four force plates mounted a movable platform. They pyridoxine (350 mg/kg, i.p.) 2 successive days (0 and 1). Electromyographic (EMG) activity was recorded from selected hindlimb muscles during linear ramp-and-hold platform each 12 directions at 15 cm/sec. In control trials onset latencies evoked flexor extensor ranged 40 65 msec after acceleration. After injection EMG increased over days, becoming two three times longer than controls by day 7. Excursions body center mass (CoM) direction opposite that translation significantly greater 7 compared with controls, time which CoM subsequently reversed delayed. Both animals ataxic onward. Histological analysis cutaneous muscle nerves revealed significant group I range. Our results suggest afferent are critical for timing ensure coordinated balance unexpected disturbances surface.