Tuning of the spinal generators: modelling study

Area of Science:

• Neuroscience
• Computational Neuroscience
• Motor Control Systems

Background:

• Locomotion in mammals involves complex coordination of limb movements.
• Spinal generators are crucial for generating rhythmic motor patterns.
• Understanding the control mechanisms of spinal generators is essential for motor control research.

Purpose of the Study:

• To design a computational model of a neuronal network within the spinal generator responsible for coordinating limb movements.
• To investigate the minimal control signals required for regulating locomotor patterns.
• To test hypotheses regarding the role of supraspinal influences and spinal subsystems in limb coordination.

Main Methods:

• Development of a neuronal network model using analog inhibitory neurons.
• Verification of the model using electrophysiological and behavioral data from cat locomotion studies.
• Analysis of the model's response to different control signal inputs.

Main Results:

• The model supports the hypothesis that supraspinal influences dictate the excitation level and coupling of spinal subsystems for limb coordination.
• Control of the model's motor output can be achieved solely through tonic excitatory signals.
• The study proposes two functional subsystems within spinal structures: one for the general locomotor cycle and another for individual muscle activity control.

Conclusions:

• Limb coordination during locomotion is orchestrated by supraspinal inputs modulating spinal subsystems.
• A simplified control mechanism involving tonic excitatory signals can effectively regulate complex motor patterns.
• The spinal cord likely comprises distinct subsystems for generating the overall movement cycle and fine-tuning muscle activation.