A silicon central pattern generator controls locomotion in vivo

Area of Science:

• Neuroscience
• Biomedical Engineering
• Robotics

Background:

• Spinal central pattern generators (CPGs) are neural circuits responsible for generating rhythmic motor patterns, such as walking.
• Neuromorphic engineering seeks to replicate biological neural systems in silicon for advanced computation and control.
• Restoring locomotion in individuals with paralysis remains a significant challenge in neurorehabilitation.

Purpose of the Study:

• To develop and validate a neuromorphic silicon chip emulating a biological spinal CPG.
• To demonstrate the chip's ability to generate locomotor patterns for walking.
• To test the in vivo efficacy of the neuromorphic device in restoring motor function in a paralyzed animal model.

Main Methods:

• Designed a neuromorphic chip with ten integrate-and-fire silicon neurons and 190 programmable digital-to-analog converters acting as synapses.
• Implemented a flexible architecture allowing complex synaptic connections between neurons and external inputs.
• Conducted experiments controlling the motor output of a paralyzed animal using the silicon CPG in real-time, incorporating closed-loop sensory feedback.

Main Results:

• The neuromorphic chip successfully emulated CPG activity and generated functional locomotor patterns.
• The chip controlled the motor output of a paralyzed animal, enabling it to walk on a platform.
• Closed-loop control using sensory feedback from the animal's legs was effectively integrated with the silicon CPG.

Conclusions:

• This work presents the first in vivo demonstration of a neuromorphic device replacing functions of the central nervous system for locomotion.
• The developed silicon CPG offers a promising platform for restoring motor function in paralysis.
• The study highlights the potential of neuromorphic engineering in creating advanced brain-computer interfaces for neuroprosthetics.