@article {68885, title = {A rise-to-threshold process for a relative-value decision.}, journal = {Nature}, volume = {619}, year = {2023}, month = {2023 Jul 05}, pages = {563-571}, abstract = {

Whereas progress has been made in the identification of neural signals related to rapid, cued decisions, less is known about how brains guide and terminate more ethologically relevant decisions in which an animal{\textquoteright}s own behaviour governs the options experienced over minutes. Drosophila search for many seconds to minutes for egg-laying sites with high relative value and have neurons, called oviDNs, whose activity fulfills necessity and sufficiency criteria for initiating the egg-deposition motor programme. Here we show that oviDNs express a calcium signal that (1) dips when an egg is internally prepared (ovulated), (2) drifts up and down over seconds to minutes-in a manner influenced by the relative value of substrates-as a fly determines whether to lay an egg and (3) reaches a consistent peak level just before the abdomen bend for egg deposition. This signal is apparent in the cell bodies of oviDNs in the brain and it probably reflects a behaviourally relevant rise-to-threshold process in the ventral nerve cord, where the synaptic terminals of oviDNs are located and where their output can influence behaviour. We provide perturbational evidence that the egg-deposition motor programme is initiated once this process hits a threshold and that subthreshold variation in this process regulates the time spent considering options and, ultimately, the choice taken. Finally, we identify a small recurrent circuit that feeds into oviDNs and show that activity in each of its constituent cell types is required for laying an egg. These results argue that a rise-to-threshold process regulates a relative-value, self-paced decision and provide initial insight into the underlying circuit mechanism for building this process.

}, issn = {1476-4687}, doi = {10.1038/s41586-023-06271-6}, author = {Vijayan, Vikram and Wang, Fei and Wang, Kaiyu and Chakravorty, Arun and Adachi, Atsuko and Akhlaghpour, Hessameddin and Dickson, Barry J and Maimon, Gaby} } @article {65859, title = {Neural circuit mechanisms of sexual receptivity in Drosophila females.}, journal = {Nature}, volume = {589}, year = {2021}, month = {2021 Jan 01}, pages = {577-81}, abstract = {

Choosing a mate is one of the most consequential decisions a female will make during her lifetime. A female fly signals her willingness to mate by opening her vaginal plates, allowing a courting male to copulate. Vaginal plate opening (VPO) occurs in response to the male courtship song and is dependent on the mating status\ of the female. How these exteroceptive (song) and interoceptive (mating status) inputs are integrated to regulate VPO remains unknown. Here we characterize the neural circuitry that implements mating decisions in the brain of female Drosophila melanogaster. We show that VPO is controlled by a pair of female-specific descending neurons (vpoDNs). The vpoDNs receive excitatory input from auditory neurons (vpoENs), which are tuned to specific features of the D. melanogaster song, and from pC1 neurons, which encode the mating status\ of the female. The song responses of vpoDNs, but not vpoENs, are attenuated upon mating, accounting for the reduced receptivity of mated females. This modulation is mediated by pC1 neurons. The vpoDNs thus directly integrate the external and internal signals that control the mating decisions of Drosophila females.

}, issn = {1476-4687}, doi = {10.1038/s41586-020-2972-7}, author = {Wang, Kaiyu and Wang, Fei and Forknall, Nora and Yang, Tansy and Patrick, Christopher and Parekh, Ruchi and Dickson, Barry J} } @article {65683, title = {Circuit and behavioral mechanisms of sexual rejection by drosophila females.}, journal = {Current Biology}, volume = {30}, year = {2020}, month = {2020 Oct 05}, abstract = {

The mating decisions of Drosophila melanogaster females are primarily revealed through either of two discrete actions: opening of the vaginal plates to allow copulation, or extrusion of the ovipositor to reject the male. Both actions are triggered by the male courtship song, and both are dependent upon the female{\textquoteright}s mating status. Virgin females are more likely to open their vaginal plates in response to song; mated females are more likely to extrude their ovipositor. Here, we examine the neural cause and behavioral consequence of ovipositor extrusion. We show that the DNp13 descending neurons act as command-type neurons for ovipositor extrusion, and that ovipositor extrusion is an effective deterrent only when performed by females that have previously mated. The DNp13 neurons respond to male song via direct synaptic input from the pC2l auditory neurons. Mating status does not modulate the song responses of DNp13 neurons, but rather how effectively they can engage the motor circuits for ovipositor extrusion. We present evidence that mating status information is mediated by ppk sensory neurons in the uterus, which are activated upon ovulation. Vaginal plate opening and ovipositor extrusion are thus controlled by anatomically and functionally distinct circuits, highlighting the diversity of neural decision-making circuits even in the context of closely related behaviors with shared exteroceptive and interoceptive inputs.

}, issn = {1879-0445}, doi = {10.1016/j.cub.2020.07.083}, author = {Wang, Fei and Wang, Kaiyu and Forknall, Nora and Parekh, Ruchi and Dickson, Barry J} } @article {65317, title = {Neural circuitry linking mating and egg laying in Drosophila females.}, journal = {Nature}, volume = {579}, year = {2020}, month = {2020 Mar 02}, pages = {101-105}, abstract = {

Mating and egg laying are tightly cooordinated events in the reproductive life of\ all oviparous females. Oviposition is typically rare in virgin females but is initiated after copulation. Here we identify the neural circuitry that links egg laying to mating status in Drosophila melanogaster. Activation of female-specific oviposition descending neurons (oviDNs) is necessary and sufficient for egg laying, and is equally potent in virgin and mated females. After mating, sex peptide-a protein from the male seminal fluid-triggers many behavioural and physiological changes in the female, including the onset of egg laying. Sex peptide is detected by sensory neurons in the uterus, and silences these neurons and their postsynaptic ascending neurons in the abdominal ganglion. We show that these\ abdominal ganglion neurons directly activate the female-specific pC1 neurons. GABAergic (γ-aminobutyric-acid-releasing) oviposition inhibitory neurons (oviINs) mediate feed-forward inhibition from pC1 neurons to both oviDNs and their major excitatory input, the oviposition excitatory neurons (oviENs). By attenuating the abdominal ganglion inputs to pC1 neurons and oviINs, sex peptide disinhibits oviDNs to enable egg laying after mating. This circuitry thus coordinates the two key events in female reproduction: mating and egg laying.

}, issn = {1476-4687}, doi = {10.1038/s41586-020-2055-9}, author = {Wang, Fei and Wang, Kaiyu and Forknall, Nora and Patrick, Christopher and Yang, Tansy and Parekh, Ruchi and Bock, Davi and Dickson, Barry J} }