Dimensionality reduction simplifies synaptic partner matching in an olfactory circuit.

Area of Science:

• Neuroscience
• Developmental Biology
• Computational Neuroscience

Background:

• Axon guidance in three-dimensional (3D) space is crucial for forming neural circuits.
• Understanding how axons find specific synaptic partners is a fundamental question in neuroscience.

Purpose of the Study:

• To investigate the principles governing the formation of the 3D glomerular map in the fly antennal lobe.
• To elucidate the strategy employed by olfactory receptor neuron (ORN) axons in locating their postsynaptic partners.

Main Methods:

• Developmental analysis of ORN axon targeting within the fly antennal lobe.
• Examination of axon trajectories and their relationship to target glomeruli.
• Perturbation experiments to assess the impact of altered trajectories on synaptic partner matching.

Main Results:

• ORN axons initially contact projection neuron (PN) dendrites at the 2D surface of the antennal lobe during development.
• Axons of each ORN type follow specific 1D arc-shaped trajectories along the antennal lobe surface.
• These trajectories precisely intersect with their corresponding PN dendrites, ensuring accurate synaptic connections.

Conclusions:

• A dimensionality reduction principle simplifies the 3D search for synaptic partners.
• The 1D trajectory strategy facilitates precise synaptic partner matching for ORN axons.
• This wiring principle may be conserved in the development of more complex brain circuits.