Spatiotemporal activation of lumbar sensorimotor networks

Area of Science:

• Neuroscience
• Spinal Cord Injury Research
• Animal Models

Background:

• Rodent models are common in spinal cord injury (SCI) research but often fail to translate to human clinical trials.
• Yucatan miniature pigs (minipigs) present a promising large animal model due to anatomical similarities with humans.
• Limited understanding of minipig spinal cord neural architecture hinders their use in SCI research.

Purpose of the Study:

• To map the functional architecture of sensorimotor networks in the minipig lumbosacral spinal cord.
• To investigate the distinctness of motor and sensory pathways within the minipig spinal cord.
• To establish a foundation for using minipigs in translational SCI research.

Main Methods:

• Implantation of a clinical-grade epidural paddle array over the lumbosacral enlargement in four minipigs.
• Mapping topographical distribution of spinally evoked motor potentials in hindlimb muscles.
• Recording cord dorsum potentials evoked by sub-motor threshold tibial nerve stimulation.

Main Results:

• Spatial correlation analysis indicated distinct and separate motor and sensory networks innervated by the tibial nerve.
• Sensorimotor networks are functionally diffused across the lumbar enlargement with unique spatiotemporal activation patterns.
• Electrophysiological measures showed significant inter-animal variability, suggesting a need for individualized approaches.

Conclusions:

• This study provides foundational knowledge of minipig sensorimotor networks, crucial for translational SCI research.
• The findings support the use of epidural paddle arrays for mapping motor responses, demonstrating clinical feasibility.
• Results highlight the subject-specific nature of electrophysiological maps and sensitivity to array placement, informing future study designs.