Formation of somatosensory detour circuits mediates functional recovery following dorsal column injury

Scientific Reports, 2020 · DOI: 10.1038/s41598-020-67866-x · Published: July 9, 2020

Simple Explanation

Following spinal cord injuries, the body can sometimes recover function through the formation of new intraspinal detour circuits. This study investigates how mice recover tactile and proprioceptive function after a specific type of spinal cord injury. After injury, sensory fibers from dorsal root ganglion (DRG) axons increase branching in the spinal grey matter, integrating into spinal networks. The number of contacts between DRG collaterals and spinal neurons also increases significantly. The study found that these detour circuits, formed through the remodeling of connections, are crucial for the recovery of tactile and proprioceptive function after dorsal column injury.

Study Duration

12 weeks

Participants

Mice

Evidence Level

Not specified

Key Findings

1
Unilateral dorsal column lesions in mice are followed by recovery of tactile and proprioceptive function.
2
DRG axons sprout new collaterals caudal to the lesion site, establishing new synaptic contacts in the cervical grey matter.
3
Emerging DRG collaterals preferentially contact inhibitory relay neurons, particularly parvalbumin-positive neurons.

Research Summary

This study investigates the structural adaptation of the ascending medial lemniscal pathway following a cervical dorsal column lesion in mice to reveal the rewiring strategies of sensory circuits. The research demonstrates that remodeling of somatosensory afferents is induced spontaneously following a dorsal column lesion and directly contributes to the recovery of sensory function, including proprioception and the sense of touch. The study establishes that proprioceptive function following a dorsal column lesion can recover and that this recovery is, at least in part, mediated by the spontaneous formation of intraspinal detour circuits that reconnect the transected DRG axons with their original target area.

Practical Implications

Therapeutic target

The formation of intraspinal detour circuits might represent a promising therapeutic target for the restoration of motor and sensory function in spinal cord injured patients.

Understanding Recovery Mechanisms

The findings suggest that recovery mechanisms are similar between the motor and somatosensory system and conserved across species.

Clinical Application

The study indicates that common principles guide rewiring processes in both motor and somatosensory systems, highlighting the formation of intraspinal detour circuits as a key structural element.

Study Limitations

1
The study is limited to mice, and findings may not directly translate to humans.
2
The focus is primarily on the dorsal column-medial lemniscal pathway; other pathways may also contribute to recovery.
3
The mechanisms guiding the formation of detour circuits are still being unraveled.

Your Feedback

Was this summary helpful?

Back to Spinal Cord Injury