Synaptic targets of photoreceptors specialized to detect color and skylight polarization in Drosophila
- Freie Universität Berlin, Germany
- Howard Hughes Medical Institute, United States
Abstract
Color and polarization provide complementary information about the world and are detected by specialized photoreceptors. However, the downstream neural circuits that process these distinct modalities are incompletely understood in any animal. Using electron microscopy, we have systematically reconstructed the synaptic targets of the photoreceptors specialized to detect color and skylight polarization in Drosophila, and we have used light microscopy to confirm many of our findings. We identified known and novel downstream targets that are selective for different wavelengths or polarized light, and followed their projections to other areas in the optic lobes and the central brain. Our results revealed many synapses along the photoreceptor axons between brain regions, new pathways in the optic lobes, and spatially segregated projections to central brain regions. Strikingly, photoreceptors in the polarization-sensitive dorsal rim area target fewer cell types, and lack strong connections to the lobula, a neuropil involved in color processing. Our reconstruction identifies shared wiring and modality-specific specializations for color and polarization vision, and provides a comprehensive view of the first steps of the pathways processing color and polarized light inputs.
Data availability
All data generated or analyzed during this study are included in the manuscript and supporting files. Supplementary File 1 and 3 contain all connectivity data. Supplementary File 2 provides images of all EM skeletons.All code and necessary data to perform the analysis and generate the figures of this manuscript will be available from https://github.com/reiserlab.All reconstructed neurons described in the manuscript will be made available at https://fafb.catmaid.virtualflybrain.org/.
Article and author information
Author details
Funding
Howard Hughes Medical Institute
- Kit D Longden
- Aljoscha Nern
- Arthur Zhao
- Miriam A Flynn
- Connor W Laughland
- Bruck Gezahegn
- Henrique DF Ludwig
- Alex G Thomson
- Heather Dionne
- Davi D Bock
- Gerald M Rubin
- Michael B Reiser
Freie Universität Berlin
- Emil Kind
- Gizem Sancer
- Tessa Obrusnik
- Paula G Alarcón
- Mathias F Wernet
Deutsche Forschungsgemeinschaft (WE 5761/2-1)
- Mathias F Wernet
Deutsche Forschungsgemeinschaft (WE 5761/4-1)
- Mathias F Wernet
Air Force Office of Scientific Research (FA9550-19-1-7005)
- Mathias F Wernet
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2021, Kind et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 3,076
- views
-
- 483
- downloads
-
- 50
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
Further reading
-
- Neuroscience
By influencing calcium homeostasis, local protein synthesis and the endoplasmic reticulum, a small protein called Rab10 emerges as a crucial cytoplasmic regulator of neuropeptide secretion.
-
- Neuroscience
The infralimbic cortex (IL) is essential for flexible behavioral responses to threatening environmental events. Reactive behaviors such as freezing or flight are adaptive in some contexts, but in others a strategic avoidance behavior may be more advantageous. IL has been implicated in avoidance, but the contribution of distinct IL neural subtypes with differing molecular identities and wiring patterns is poorly understood. Here, we study IL parvalbumin (PV) interneurons in mice as they engage in active avoidance behavior, a behavior in which mice must suppress freezing in order to move to safety. We find that activity in inhibitory PV neurons increases during movement to avoid the shock in this behavioral paradigm, and that PV activity during movement emerges after mice have experienced a single shock, prior to learning avoidance. PV neural activity does not change during movement toward cued rewards or during general locomotion in the open field, behavioral paradigms where freezing does not need to be suppressed to enable movement. Optogenetic suppression of PV neurons increases the duration of freezing and delays the onset of avoidance behavior, but does not affect movement toward rewards or general locomotion. These data provide evidence that IL PV neurons support strategic avoidance behavior by suppressing freezing.
