More Like this

1. Intestine-to-neuronal signaling alters risk-taking behaviors in food-deprived Caenorhabditis elegans

   https://doi.org/10.1371/journal.pgen.1010178  

   Matty, Molly A.; Lau, Hiu E.; Haley, Jessica A.; Singh, Anupama; Chakraborty, Ahana; Kono, Karina; Reddy, Kirthi C.; Hansen, Malene; Chalasani, Sreekanth H. (May 2022, PLOS Genetics)

   Ashrafi, Kaveh (Ed.)

   Animals integrate changes in external and internal environments to generate behavior. While neural circuits detecting external cues have been mapped, less is known about how internal states like hunger are integrated into behavioral outputs. Here, we use the nematode C . elegans to examine how changes in internal nutritional status affect chemosensory behaviors. We show that acute food deprivation leads to a reversible decline in repellent, but not attractant, sensitivity. This behavioral change requires two conserved transcription factors MML-1 (MondoA) and HLH-30 (TFEB), both of which translocate from the intestinal nuclei to the cytoplasm during food deprivation. Next, we identify the insulin-like peptide INS-31 as a candidate ligand relaying food-status signals from the intestine to other tissues. Further, we show that neurons likely use the DAF-2 insulin receptor and AGE-1/PI-3 Kinase, but not DAF-16/FOXO to integrate these intestine-released peptides. Altogether, our study shows how internal food status signals are integrated by transcription factors and intestine-neuron signaling to generate flexible behaviors via the gut-brain axis. 

   more » « less
2. Diverse states and stimuli tune olfactory receptor expression levels to modulate food-seeking behavior

   https://doi.org/10.7554/eLife.79557  

   McLachlan, Ian G; Kramer, Talya S; Dua, Malvika; DiLoreto, Elizabeth M; Gomes, Matthew A; Dag, Ugur; Srinivasan, Jagan; Flavell, Steven W (August 2022, eLife)

   Animals must weigh competing needs and states to generate adaptive behavioral responses to the environment. Sensorimotor circuits are thus tasked with integrating diverse external and internal cues relevant to these needs to generate context-appropriate behaviors. However, the mechanisms that underlie this integration are largely unknown. Here, we show that a wide range of states and stimuli converge upon a single Caenorhabditis elegans olfactory neuron to modulate food-seeking behavior. Using an unbiased ribotagging approach, we find that the expression of olfactory receptor genes in the AWA olfactory neuron is influenced by a wide array of states and stimuli, including feeding state, physiological stress, and recent sensory cues. We identify odorants that activate these state-dependent olfactory receptors and show that altered expression of these receptors influences food-seeking and foraging. Further, we dissect the molecular and neural circuit pathways through which external sensory information and internal nutritional state are integrated by AWA. This reveals a modular organization in which sensory and state-related signals arising from different cell types in the body converge on AWA and independently control chemoreceptor expression. The synthesis of these signals by AWA allows animals to generate sensorimotor responses that reflect the animal’s overall state. Our findings suggest a general model in which sensory- and state-dependent transcriptional changes at the sensory periphery modulate animals’ sensorimotor responses to meet their ongoing needs and states. 

   more » « less
3. Orcokinin neuropeptides regulate sleep in Caenorhabditis elegans

   https://doi.org/10.1080/01677063.2020.1830084  

   Honer, Madison; Buscemi, Kristen; Barrett, Natalie; Riazati, Niknaz; Orlando, Gerald; Nelson, Matthew D. (January 2020, Journal of Neurogenetics)

   Orcokinin neuropeptides are conserved among ecdysozoans, but their functions are incompletely understood. Here, we report a role for orcokinin neuropeptides in the regulation of sleep in the nematode Caenorhabditis elegans. The C. elegans orcokinin peptides, which are encoded by the nlp-14 and nlp-15 genes, are necessary and sufficient for quiescent behaviors during developmentally timed sleep (DTS) as well as during stress-induced sleep (SIS). The five orcokinin neuropeptides encoded by nlp-14 have distinct but overlapping functions in the regulation of movement and defecation quiescence during SIS. We suggest that orcokinins may regulate behavioral components of sleep-like states in nematodes and other ecdysozoans. 

   more » « less
4. A neural circuit for flexible control of persistent behavioral states

   https://doi.org/10.7554/eLife.62889  

   Ji, Ni; Madan, Gurrein K; Fabre, Guadalupe I; Dayan, Alyssa; Baker, Casey M; Kramer, Talya S; Nwabudike, Ijeoma; Flavell, Steven W (November 2021, eLife)

   To adapt to their environments, animals must generate behaviors that are closely aligned to a rapidly changing sensory world. However, behavioral states such as foraging or courtship typically persist over long time scales to ensure proper execution. It remains unclear how neural circuits generate persistent behavioral states while maintaining the flexibility to select among alternative states when the sensory context changes. Here, we elucidate the functional architecture of a neural circuit controlling the choice between roaming and dwelling states, which underlie exploration and exploitation during foraging in C. elegans . By imaging ensemble-level neural activity in freely moving animals, we identify stereotyped changes in circuit activity corresponding to each behavioral state. Combining circuit-wide imaging with genetic analysis, we find that mutual inhibition between two antagonistic neuromodulatory systems underlies the persistence and mutual exclusivity of the neural activity patterns observed in each state. Through machine learning analysis and circuit perturbations, we identify a sensory processing neuron that can transmit information about food odors to both the roaming and dwelling circuits and bias the animal towards different states in different sensory contexts, giving rise to context-appropriate state transitions. Our findings reveal a potentially general circuit architecture that enables flexible, sensory-driven control of persistent behavioral states. 

   more » « less
5. Challenges in Behavioral Code Clone Detection

   https://doi.org/10.1109/SANER.2016.75  

   Su, Fang-Hsiang; Bell, Jonathan; Kaiser, Gail (March 2016, 2016 IEEE 23rd International Conference on Software Analysis, Evolution, and Reengineering (SANER))

   When software engineering researchers discuss "similar" code, we often mean code determined by static analysis to be textually, syntactically or structurally similar, known as code clones (looks alike). Ideally, we would like to also include code that is behaviorally or functionally similar, even if it looks completely different. The state of the art in detecting these behavioral clones focuses on checking the functional equivalence of the inputs and outputs of code fragments, regardless of its internal behavior (focusing only on input and output states). We argue that with an advance in dynamic code clone detection towards detecting behavioral clones (i.e., those with similar execution behavior), we can greatly increase the applications of behavioral clones as a whole for general program understanding tasks. 

   more » « less