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A rise-to-threshold signal for a relative value deliberation

Vijayan, Vikram and Wang, Fei and Wang, Kaiyu and Chakravorty, Arun and Adachi, Atsuko and Akhlaghpour, Hessameddin and Dickson, Barry J. and Maimon, Gaby (2021) A rise-to-threshold signal for a relative value deliberation. . (Unpublished)

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Whereas progress has been made in identifying neural signals related to rapid, cued decisions, less is known about how brains guide and terminate more ethologically relevant deliberations, where an animal’s own behavior governs the options experienced over minutes. Drosophila search for many seconds to minutes for egg-laying sites with high relative value9 and neurons, called oviDNs, exist whose activity fulfills necessity and sufficiency criteria for initiating the egg-deposition motor program11. Here we show that oviDNs express a calcium signal that rises over seconds to minutes as a fly deliberates whether to lay an egg. The calcium signal dips when an egg is internally prepared (ovulated), rises at a rate related to the relative value of the current substrate being experienced, and reaches a consistent peak just prior to the abdomen bend for egg deposition. We provide perturbational evidence that the egg-deposition motor program is initiated once this signal hits a threshold and that sub-threshold variation in the signal regulates the time spent deliberating and, ultimately, the option chosen. These results argue that a rise-to-threshold signal guides Drosophila to lay eggs on substrate options with high relative value, with each egg-laying event representing a self-paced decision similar to real-world decisions made by humans and other mammals.

Item Type:Report or Paper (Discussion Paper)
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URLURL TypeDescription Paper
Vijayan, Vikram0000-0003-3948-7568
Akhlaghpour, Hessameddin0000-0003-0475-7169
Dickson, Barry J.0000-0003-0715-892X
Maimon, Gaby0000-0003-1219-5856
Additional Information:The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY 4.0 International license. This version posted September 24, 2021. We thank the Rockefeller University Precision Instrumentation Technologies facility for access to fabrication equipment; the Janelia FlyLight team for generating images of oviDN-GAL4 (in Fig. 1f and Extended Data Fig. 5b) and oviDN-SS1 MCFO (Fig. 1e); the Bloomington Drosophila Stock Center (NIH P400D018537) for various fly stocks; Andrew Siliciano and Vanessa Ruta for GtACR1 effector flies; Mariana Wolfer for flies expressing GCaMP in eggs; Massimo Scanziani for pCAG-Kir2.1Mut-T2A-tdTomato and pCAG-Kir2.1-T2A-tdTomato plasmids (Addgene plasmid # 60644 and 60598); Gerald Rubin for pJFRC81-10XUAS-IVS-Syn21-GFP-p10 plasmid (Addgene plasmid # 36432); Meishel DeSouto for template fly drawing that was modified and used throughout the manuscript; Zikun Wang for help developing the first iteration of the fly tracking setup; Kris Fonselius and Sam Cohen for involvement in developing tools for computer-assisted manual annotation of egg-deposition events in free behavior; Joseph Varikooty, Jonathan Hirokawa and Itzel Ishida for ideas and help developing the wheel; Jazz Weisman for sharing his design for delivery of optogenetic stimulation light; and Cheng Lyu and Jonathan Green for two-photon and electrophysiology discussions. Research reported in this publication was supported by a Brain Initiative grant from the National Institute of Neurological Disorders and Stroke (R01NS121904) to G.M. and Leon Levy Foundation fellowship and the Kavli Neural Systems Institute grant to V.V.. G.M. is a Howard Hughes Medical Institute Investigator. Author Contributions: V.V. and G.M. conceived the initial study and wrote the manuscript. V.V., with input from G.M., designed the experiments, performed the experiments, analyzed the data, interpreted the results, and decided on new experiments. F.W., K.W., and B.J.D. provided oviDN genetic driver lines and their anatomical characterization, shared preliminary data on the oviDNs, and provided helpful feedback on experiments and the manuscript. A.C. and A.A. created the Kir2.1* and Kir2.1*Mut flies. H.A. developed code for computer-assisted manual annotation of egg-deposition events in free behavior. The authors declare no competing interests. Data and Resources Availability: Datasets, code and technical documents (e.g., CAD files and plasmid maps) used in this study are available from the corresponding authors on request and will be made publicly available before or at time of publication.
Funding AgencyGrant Number
Leon Levy FoundationUNSPECIFIED
Kavli Neural Systems InstituteUNSPECIFIED
Howard Hughes Medical Institute (HHMI)UNSPECIFIED
Record Number:CaltechAUTHORS:20210929-173414065
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Official Citation:A rise-to-threshold signal for a relative value deliberation. Vikram Vijayan, Fei Wang, Kaiyu Wang, Arun Chakravorty, Atsuko Adachi, Hessameddin Akhlaghpour, Barry J. Dickson, Gaby Maimon. bioRxiv 2021.09.23.461548; doi:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:111091
Deposited By: Tony Diaz
Deposited On:29 Sep 2021 20:03
Last Modified:16 Nov 2021 19:43

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