# Spectral and spatial processing of wavelength information in the Drosophila visual system

> **NIH NIH F31** · COLUMBIA UNIVERSITY HEALTH SCIENCES · 2020 · $45,520

## Abstract

Project Summary / Abstract
 Our surroundings are extremely rich in spectral information, which confers a valuable chromatic
dimension to visual perception. In order to have the capacity for color vision, an organism must be able to
perform the necessary computations to compare light of different spectral compositions. Wavelength
comparison takes place in color opponent neurons, which respond with opposite polarity to wavelengths in
different parts of the spectrum. Despite advances in our understanding of color opponency in the brain, how
color opponent signals are transformed to give rise to the hue specificity observed in higher cortical regions
remains completely unexplained. Furthermore, how wavelength information is integrated across the visual field
to provide a spatial dimension to color vision is a poorly understood phenomenon. This project aims to
examine color pathways in the genetically tractable organism Drosophila melanogaster, as these circuits have
only just begun to be described. Drosophila provide an arsenal of genetic tools to manipulate neuronal activity
and a simple brain that makes these circuits tractable. Fruit flies have the hardware for wavelength
comparison, with wavelength-specific photoreceptors (called R7s and R8s) expressing rhodopsins sensitive to
UV, green, and blue light. There is mounting evidence that color opponency is indeed present in the brain of
the fruit fly, arising in the axons of R7/R8. Aim 1 will determine how signals are combined at the level of
photoreceptors to give rise to opponency by using two-photon calcium imaging of R7/R8 axons in a variety of
genetic backgrounds, including mutants, pairwise rescues, and lines with cell-specific silencing. Aim 2 will
elucidate the spatial nature of opponency in Drosophila photoreceptors, taking advantage of the fact that
spatially patterned stimuli will reveal potential center-surround mechanisms when paired with functional
imaging of R7/R8 axons. Finally, Aim 3 will explore the encoding of both spectral and spatial information in
downstream brain areas poised to both receive signals from photoreceptors, and to further transmit these
signals to central brain regions. There is evidence that this information eventually informs tasks such as object
recognition and spatial orientation. Determining how circuit mechanisms for spatio-chromatic processing
emerge and convey information to higher brain areas in Drosophila will provide insight into the workings of
vertebrate color pathways, as both systems employ similar mechanisms to effectively process visual
information.

## Key facts

- **NIH application ID:** 10219809
- **Project number:** 5F31EY030319-02
- **Recipient organization:** COLUMBIA UNIVERSITY HEALTH SCIENCES
- **Principal Investigator:** Sarah L Heath
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $45,520
- **Award type:** 5
- **Project period:** 2019-09-01 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10219809

## Citation

> US National Institutes of Health, RePORTER application 10219809, Spectral and spatial processing of wavelength information in the Drosophila visual system (5F31EY030319-02). Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/grant/nih/10219809. Licensed CC0.

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