Cortical Reorganization of Sensorimotor Systems and the Role of Intracortical Circuits After Spinal Cord Injury

Neurotherapeutics, 2018 · DOI: https://doi.org/10.1007/s13311-018-0638-z · Published: June 7, 2018

Spinal Cord Injury Neurology Neuroplasticity

Simple Explanation

Spinal cord injury disrupts the way the brain's motor and sensory areas are organized. This disruption happens because the injury cuts off the normal flow of information to and from the brain. After a spinal cord injury, the brain can reorganize itself to try and relearn motor skills. This reorganization relies on the brain's ability to change and adapt, using existing connections and potentially forming new ones. The connections within the brain's cortex (intracortical circuits) play a crucial role in this reorganization. By understanding how these circuits work, we can develop better rehabilitation strategies to help people recover from spinal cord injuries.

Study Duration

Not specified

Participants

Rodents and Primates

Evidence Level

Review

Key Findings

1
Spinal cord injury leads to changes in the motor cortex, with increased activity in both existing and new areas of the brain.
2
Rehabilitation can drive reorganization of trunk representations in rats after spinal cord injury, highlighting the importance of activity-dependent mechanisms.
3
Intracortical circuits, particularly in layer 2/3 neurons, undergo remodeling during motor learning, suggesting their importance in relearning movements after injury.

Research Summary

Following spinal cord injury, cortical motor and somatosensory representations undergo spontaneous reorganization, affecting neurophysiology and neuronal structure. Functional recovery and remodeling are linked to activity-dependent mechanisms, and rehabilitation elicits remodeling of cortical motor maps concomitant with behavioral recovery. Intracortical connectivity is crucial for the recovery of skilled movements, with latent connections shaping aberrant motor maps and refinement of these connections supporting rehabilitation-mediated recovery.

Practical Implications

Rehabilitation Strategies

Rehabilitation strategies after spinal cord injury should consider intracortical substrates to mediate beneficial cortical remodeling and limit maladaptive plasticity.

Therapeutic Development

Understanding the intracortical circuits that support cortical reorganization will lead to improved therapeutic and rehabilitation strategies.

Targeted Interventions

Future interventions might focus on enhancing the plasticity of specific intracortical connections to improve motor recovery after SCI.

Study Limitations

1
The review focuses on animal models (rodents, primates), and findings may not directly translate to humans.
2
The review acknowledges conflicting evidence regarding sensory cortex remodeling in rodents, indicating a need for further research.
3
The specific mechanisms of intracortical axon remodeling after spinal cord injury are not fully understood, requiring further investigation.

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