A spinal substrate for modular control of natural behavior.

Area of Science:

• Neuroscience
• Motor Control
• Animal Behavior

Background:

• Natural behaviors are complex sequences of movements.
• The neural basis for organizing these movements into discrete motor patterns is not well understood.
• Understanding motor pattern generation is key to deciphering natural behaviors.

Purpose of the Study:

• To investigate the neural circuits underlying coordinated jumping behavior in mice.
• To identify specific neuronal populations involved in generating motor patterns for locomotion.
• To explore the concept of modular motor control in the mammalian spinal cord.

Main Methods:

• Combined kinematic analysis and muscle recordings.
• Utilized genetically identified cell types and optogenetic perturbations.
• Mapped neural activity across lumbar interneuron populations.
• Functionally screened candidate cell types for their role in movement evocation.

Main Results:

• Jumping behavior consists of distinct phases with modular motor patterns.
• Propulsion and flight phases show unique neural control signatures.
• Dorsal excitatory dILB6 neurons were identified as capable of autonomously evoking hindlimb flexion patterns.
• dILB6 neurons can modulate active jumping behavior.

Conclusions:

• dILB6 spinal interneurons provide a cellular substrate for modular motor control.
• These neurons can generate coordinated multi-joint hindlimb movements across contexts.
• This research supports the idea of a flexible, preconfigured motor template in the mammalian central nervous system.