# Coordinated patterning of brain regions

> **NIH NIH R01** · NEW YORK UNIVERSITY · 2022 · $384,364

## Abstract

Project Summary
 The establishment of neuronal connectivity requires axons to select the proper neurons to form synapses with, which can
be achieved through guidance signals or through activity-dependent processes. We still have a poor understanding of the
mechanisms and molecules that direct neuronal specific connectivity pattern. The Drosophila color vision circuit offers a
powerful paradigm to study synaptic specificity because of the availability of a connectome, a deep knowledge of its
development, and powerful genetic tools to manipulate the circuit.
 In the fly retina, color photoreceptors R7 and R8 are stochastically specified, whereas their neuronal medulla targets are
produced through a highly deterministic program. We will study how this propagation is achieved. Activity-dependent
neural patterning is another powerful mean to coordinate different brain regions. Neuronal activity can occur at early
developmental stages, prior to sensory input and the onset of synaptogenesis in the form of calcium waves whose
significance has not yet been fully elucidated. We will study how early waves of activity that we observe at a very specific
time point during fly retinal development are generated and what role they play.
Aim 1. How do stochastically determined photoreceptor subtypes find their targets in the optic lobes?
 Aim 1.1. Synaptic specificity downstream of color photoreceptors: We will identify medulla neurons specific to
subsets of photoreceptors and will identify the factors involved in the recognition by their input neurons.
 Aim 1.2. Establishment of synaptic specificity downstream of R7 color photoreceptors: We will study how a
family of cell adhesion molecules allows matching between R7 cells and their Dm8 targets in the brain
 Aim 1.3. How does information from p and yR7 propagate downstream of Dm8: Once a medulla cell has made
contacts with its cognate photoreceptor, it must itself transmits this information to its downstream partners. We will
investigate how these choices are propagated down the visual pathway.
 Aim 1.4. Apoptotic pathway regulating the culling of unconnected neurons: Target neurons that are not connected
die. We will study how specific adhesion molecules regulate this death and the molecular pathways involved.
Aim 2. Mechanisms and functions of waves of spontaneous activity in the retina
 Aim 2.1. Description and cellular substrates of retinal calcium waves: We will analyze which cells are involved in
calcium waves and whether these waves propagate to downstream medulla regions.
 Aim 2.2. Molecular mechanisms of retinal calcium waves: We will study how ER calcium stores and gap junction
proteins are required to generate and propagate the waves.
 Aim 2.3. Determine the developmental role of retinal calcium waves: By disrupting the calcium waves, we will
study what role they play in patterning the retina, and/or medulla neurons that are targets of photoreceptors.

## Key facts

- **NIH application ID:** 10468607
- **Project number:** 5R01EY013010-23
- **Recipient organization:** NEW YORK UNIVERSITY
- **Principal Investigator:** Claude Desplan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $384,364
- **Award type:** 5
- **Project period:** 1999-09-01 → 2026-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10468607

## Citation

> US National Institutes of Health, RePORTER application 10468607, Coordinated patterning of brain regions (5R01EY013010-23). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10468607. Licensed CC0.

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