Gap junctions desynchronize a neural circuit to stabilize insect flight

Area of Science:

• Neuroscience
• Biophysics
• Insect Physiology

Background:

• Insect asynchronous flight is crucial for locomotion in over 600,000 species.
• While motor patterns, biomechanics, and aerodynamics are understood, the central-pattern-generating (CPG) neural network's architecture and function remain elusive.

Purpose of the Study:

• To elucidate the architecture and function of the CPG neural network underlying insect asynchronous flight.
• To identify the circuit mechanisms responsible for generating rhythmic motor patterns for flight control.

Main Methods:

• Combined electrophysiology, optophysiology, and Drosophila genetics.
• Employed mathematical modeling to analyze neural network dynamics.
• Investigated the role of electrical synapses in CPG function.

Main Results:

• Identified a miniaturized CPG circuit with motoneurons interconnected by electrical synapses.
• Demonstrated that weak electrical synapses, contrary to expectations, desynchronize network activity.
• Showcased a generic mechanism for network desynchronization dependent on neuron excitability and synapse strength.
• Confirmed this desynchronization mechanism translates unpatterned input into stereotyped neuronal firing for stable wing power.
• Found this mechanism is conserved across multiple insect species.

Conclusions:

• Electrical synapses exhibit greater functional versatility in neural circuit control than previously thought.
• The identified desynchronization mechanism is key to stable wing power generation in asynchronous flight.
• Highlights the importance of detecting electrical synapses in connectomics research for understanding neural circuits.