Synergistic interaction between sensory inputs and propriospinal signalling underlying quadrupedal locomotion.

Area of Science:

• Neuroscience
• Locomotion Biology
• Spinal Cord Research

Background:

• Quadrupedal locomotion requires coordination between cervical and lumbar central pattern generators (CPGs).
• Propriospinal and sensory pathways are thought to mediate CPG interaction, but their combined effects are unclear.

Purpose of the Study:

• To investigate the functional consequences of sensory and propriospinal pathway involvement on forelimb and hindlimb CPG coordination.
• To understand how hindlimb afferent stimulation influences fictive locomotion.

Main Methods:

• Used an in vitro brainstem/spinal cord preparation of neonatal rat.
• Stimulated hindlimb afferent fibres and dorsal roots during pharmacologically induced fictive locomotion.
• Employed split-bath experiments to isolate cervical and lumbar CPG activity.

Main Results:

• Hindlimb sensory input elicited coordinated hindlimb and forelimb CPG activity.
• Lumbar dorsal root stimulation stabilized locomotor rhythm and increased motoneuron activity, including doublets.
• Propriospinal and sensory pathways synergistically enhanced cervico-lumbar interactions.

Conclusions:

• Sensory and propriospinal pathways interact synergistically to couple forelimb and hindlimb CPGs.
• This coupling is essential for effective quadrupedal locomotion.
• Hindlimb afferent stimulation plays a crucial role in coordinating CPG activity.