Spinal projections from the presumptive midbrain locomotor region in the mouse

Area of Science:

• Neuroscience
• Locomotion Control
• Spinal Cord Anatomy

Background:

• The mesencephalic locomotor region (MLR) is vital for locomotion control.
• The precise spinal connections of the MLR remain incompletely understood.

Purpose of the Study:

• To investigate the spinal projections of the mouse precuneiform nucleus (PrCnF), a component of the MLR.
• To elucidate the anatomical substrate underlying MLR's role in locomotion.

Main Methods:

• Utilized retrograde (Fluoro-Gold) and anterograde (biotinylated dextran amine) neuronal tracing techniques in mice.
• Examined PrCnF neuronal labeling following injections in the upper cervical and thoracic spinal cord.
• Tracked labeled fibers in the spinal cord after PrCnF tracer injections.

Main Results:

• Retrograde labeling showed PrCnF neurons projecting to the upper cervical spinal cord, with fewer projections to the thoracic levels.
• Anterograde tracing revealed PrCnF fibers extending into the ventral and lateral funiculi of the spinal cord.
• Terminations were predominantly observed in spinal cord laminae 7, 8, 9, and area 10, with an ipsilateral bias.

Conclusions:

• The PrCnF exhibits significant projections to the cervical spinal cord.
• These projections likely contribute to the MLR's control over locomotion.
• This study provides key anatomical insights into the MLR-spinal cord circuitry.