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Updated: Apr 21, 2026

In Vivo Intracellular Recording of Type-Identified Rat Spinal Motoneurons During Trans-Spinal Direct Current Stimulation
Published on: May 11, 2020
Innervation and function of rat tail muscles for modeling cauda equina injury and repair
Samuel J MacKenzie1, Juneyoung L Yi2, Amit Singla2
1Department of Neuroscience, Upstate Medical University, Syracuse, New York, USA.
Introduction:
The rat tail exhibits functional impairment after cauda equina injury. Our goal was to better understand the innervation and roles of muscles that control the tail.
Methods:
Adult rats received either: (1) ventral root injury; (2) caudales nerve injury; or (3) mapping of sacrococcygeal myotomes. Activation of small muscles within the tail itself (intrinsics) was compared with that of larger lumbosacral muscles acting on the tail (extrinsics). Behavioral testing of tail movement was done 1 week later.
Results:
Rats that received ventral root injury exhibited multiple behavioral deficits, whereas rats with injury to caudales nerves maintained more fully preserved tail movement. Mapping studies revealed much broader overlap of myotomes for extrinsic muscles.
Conclusions:
Extrinsic tail muscles play a greater role in tail movement in the rat than their intrinsic counterparts and are innervated by multiple neurological segments. These findings have major implications for future research on cauda equina injury.

