Fictive rhythmic motor patterns produced by the tail spinal cord in salamanders

Area of Science:

• Neuroscience
• Comparative Physiology
• Locomotion Biology

Background:

• Vertebrate locomotion research often overlooks the tail's active role, despite its significance in tetrapods.
• In salamanders, the tail is crucial for propulsion during swimming and balance/maneuverability during terrestrial movement.

Purpose of the Study:

• To investigate the neural mechanisms underlying tail muscle contractions during locomotion in the salamander, *Pleurodeles waltlii*.
• To characterize the spinal cord's role in generating rhythmic tail movements.

Main Methods:

• In vitro spinal cord preparations were used, inducing locomotor-like activity with N-methyl-d-aspartate and d-serine.
• Ventral root activities were recorded to analyze motor patterns.
• Lesion experiments and partitioned chamber recordings were employed to study network organization and coupling.

Main Results:

• The tail spinal cord demonstrated the capacity to generate propagated, alternating left-right motor activity waves.
• Lesion studies identified the tail rhythmogenic network as a double chain of hemisegmental oscillators.
• Efficient short-distance coupling between trunk and tail locomotor networks was observed.

Conclusions:

• A pattern generator for rhythmic tail movements exists in salamanders, with a network architecture similar to the trunk.
• These findings support independent control of trunk and tail movements in salamanders.
• The study provides insights into the neural basis of tail muscle activation during locomotion.