# Assembly of the Central Olfactory Networks in Drosophila

> **NIH NIH R01** · STANFORD UNIVERSITY · 2020 · $332,613

## Abstract

From insects to mammals, olfactory receptor neurons (ORNs) expressing the same odorant receptor
target their axonal projections to specific glomerular destinations in the antennal lobe/olfactory bulb,
creating an odor map in these first olfactory structures of the central nervous system. In the fly,
axons of 50 classes of ORNs match precisely with dendrites of corresponding 50 classes of second
order olfactory projection neurons (PNs) to form the 50 glomeruli of the antennal lobe. Olfactory
information is thus faithfully delivered from sensory organs in the periphery to higher brain centers,
enabling innate and learned olfactory behavior.
 Thanks to the continual support of this grant since 2003, our studies have made the Drosophila
antennal lobe one of the best-understood circuits in terms of the molecular, cellular, and
developmental underpinnings of wiring specificity. We provided a detailed description of the wiring
process with single-cell resolution, finding that PN dendrites pre-pattern the antennal lobe prior to
ORN axon invasion. We discovered the importance of PN dendrite-dendrite, ORN axon-axon, and PN
dendrite-ORN axon interactions and some of the underlying molecular mechanisms. Moreover, we
recently developed methods to profile the transcriptomes of individual olfactory neurons, and to
visualize them as they make wiring decisions using time-lapse imaging.
 In this renewal, we propose to combine live imaging, single-cell RNA-sequencing, proteomic
approaches with state-of-the-art genetic manipulations to address the following three questions: 1)
how do ORN axons choose a specific trajectory when they first reach the antennal lobe? 2) How do
PN dendrites establish discrete boundaries and targeting specificity? 3) How do ORN axons find their
partner PN dendrites? The completion of the proposed studies will allow us to gain a more
comprehensive understanding of the combinatorial codes that determine wiring specificity, and cell
biological mechanisms that underlying the execution of wiring decisions.
 These studies will contribute to our understanding of a central problem in developmental
neurobiology: how wiring specificity of neural circuits is achieved during development. By uncovering
the molecules and mechanisms inherent to the fly olfactory circuit, we have already provided insight
into constructing more complex neural circuits in the mammalian brain, and established links between
neural circuit wiring and disorders of the human brain.

## Key facts

- **NIH application ID:** 9891999
- **Project number:** 5R01DC005982-18
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** LIQUN LUO
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $332,613
- **Award type:** 5
- **Project period:** 2003-04-06 → 2023-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9891999

## Citation

> US National Institutes of Health, RePORTER application 9891999, Assembly of the Central Olfactory Networks in Drosophila (5R01DC005982-18). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9891999. Licensed CC0.

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