Sparing of Descending Axons Rescues Interneuron Plasticity in the Lumbar Cord to Allow Adaptive Learning After Thoracic Spinal Cord Injury

Front. Neural Circuits, 2016 · DOI: 10.3389/fncir.2016.00011 · Published: March 2, 2016

Spinal Cord Injury Neurology Neuroplasticity

Simple Explanation

This study explores how spared axons after a spinal cord injury (SCI) influence the ability of the lumbar spinal cord to learn and adapt. The study uses a model where rats learn to flex their leg to avoid a shock, testing if spared axons help the spinal cord learn this task after a thoracic SCI. The findings suggest that spared axons promote adaptive changes in the lumbar cord, allowing for better learning and preventing maladaptive plasticity after SCI.

Study Duration

7 or 42 days

Participants

Adult female Sprague Dawley rats

Evidence Level

Not specified

Key Findings

1
Spared axons are critical for adaptive plasticity in lumbar interneurons after thoracic SCI, enabling locomotor learning.
2
Without spared axons, lumbar interneurons develop a hyperexcitable phenotype and fail to support normal learning after SCI.
3
Exposure to spared axons prevents neuronal atrophy and aberrant spine formations in lumbar interneurons.

Research Summary

The study investigates the role of spared axons on neuroplasticity in the lumbar enlargement after thoracic SCI, using an instrumental learning paradigm (ILP). Early after SCI (7 days), spinal learning was unattainable regardless of axonal substrate, with cell soma atrophy and aberrant dendritic spine expression. However, after 6 weeks, spared axons produced near-normal learning. The findings highlight a time-dependent interaction between spared axonal systems and adaptive plasticity in locomotor networks, identifying a critical window for activity-based rehabilitation.

Practical Implications

Rehabilitation Timing

The timing of rehabilitation is critical. Interventions should be timed to coincide with the window when spared axons can best influence plasticity in the lumbar cord.

Targeted Therapies

Therapeutic strategies should focus on facilitating the integration between spared axonal relays and pattern generator networks to enhance motor relearning and recovery.

Understanding Spasticity

The findings may provide insights into the mechanisms underlying spasticity and other below-level functional deficits after SCI, potentially leading to more effective treatments.

Sparing of Descending Axons Rescues Interneuron Plasticity in the Lumbar Cord to Allow Adaptive Learning After Thoracic Spinal Cord Injury

Simple Explanation

Key Findings

Research Summary

Practical Implications

Rehabilitation Timing

Targeted Therapies

Understanding Spasticity

Study Limitations

Your Feedback

Was this summary helpful?

Sparing of Descending Axons Rescues Interneuron Plasticity in the Lumbar Cord to Allow Adaptive Learning After Thoracic Spinal Cord Injury

Simple Explanation

Key Findings

Research Summary

Practical Implications

Rehabilitation Timing

Targeted Therapies

Understanding Spasticity

Study Limitations

Your Feedback

Was this summary helpful?