Axonal self-sorting without target guidance in Drosophila visual map formation

Area of Science:

• Neuroscience
• Developmental Biology
• Biophysics

Background:

• Axon pathfinding is crucial for brain wiring, typically relying on target-derived guidance cues.
• Understanding the mechanisms of neural superposition wiring in Drosophila offers insights into fundamental developmental processes.

Purpose of the Study:

• To investigate how axonal growth cones self-pattern during neural superposition wiring in Drosophila.
• To elucidate the role of target-dependent guidance versus self-organization in this process.

Main Methods:

• Ablation of target lamina neurons and disruption of target adhesion in Drosophila.
• High-resolution intravital imaging of growth cone dynamics in intact pupae.
• Data-driven computational simulations of growth cone behavior.

Main Results:

• Pattern development of axonal growth cones occurs even without target neurons or adhesion.
• A dynamic meshwork of over 30,000 filopodia guides growth cone direction.
• This filopodial meshwork actively steers growth, rather than exploring targets.

Conclusions:

• Axon pathfinding can be achieved through self-organization, driven by interactions among growth cones.
• Self-organization represents a fundamental mechanism in brain wiring, independent of external guidance.
• The study reveals a novel guidance mechanism emerging from collective growth cone behavior.