scholarly journals Neuronal microcircuits for decision making in C. elegans

2012 ◽  
Vol 22 (4) ◽  
pp. 580-591 ◽  
Author(s):  
S Faumont ◽  
TH Lindsay ◽  
SR Lockery
Keyword(s):  
2018 ◽  
Author(s):  
Gareth Harris ◽  
Taihong Wu ◽  
Gaia Linfield ◽  
Myung-Kyu Choi ◽  
He Liu ◽  
...  

AbstractIn the natural environment, animals often encounter multiple sensory cues that are simultaneously present. The nervous system integrates the relevant sensory information to generate behavioral responses that have adaptive values. However, the signal transduction pathways and the molecules that regulate integrated behavioral response to multiple sensory cues are not well defined. Here, we characterize a collective modulatory basis for a behavioral decision in C. elegans when the animal is presented with an attractive food source together with a repulsive odorant. We show that distributed neuronal components in the worm nervous system and several neuromodulators orchestrate the decision-making process, suggesting that various states and contexts may modulate the multisensory integration. Among these modulators, we identify a new function of a conserved TGF-β pathway that regulates the integrated decision by inhibiting the signaling from a set of central neurons. Interestingly, we find that a common set of modulators, including the TGF-β pathway, regulate the integrated response to the pairing of different foods and repellents. Together, our results provide insights into the modulatory signals regulating multisensory integration and reveal potential mechanistic basis for the complex pathology underlying defects in multisensory processing shared by common neurological diseases.Author SummaryThe present study characterizes the modulation of a behavioral decision in C. elegans when the worm is presented with a food lawn that is paired with a repulsive smell. We show that multiple sensory neurons and interneurons play roles in making the decision. We also identify several modulatory molecules that are essential for the integrated decision when the animal faces a choice between the cues of opposing valence. We further show that many of these factors, which often represent different states and contexts, are common for behavioral decisions that integrate sensory information from different types of foods and repellents. Overall, our results reveal a collective molecular and cellular basis for integration of simultaneously present attractive and repulsive cues to fine-tune decision-making.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Zoë A Hilbert ◽  
Dennis H Kim

Animal behavior is directed by the integration of sensory information from internal states and the environment. Neuroendocrine regulation of diverse behaviors of Caenorhabditis elegans is under the control of the DAF-7/TGF-β ligand that is secreted from sensory neurons. Here, we show that C. elegans males exhibit an altered, male-specific expression pattern of daf-7 in the ASJ sensory neuron pair with the onset of reproductive maturity, which functions to promote male-specific mate-searching behavior. Molecular genetic analysis of the switch-like regulation of daf-7 expression in the ASJ neuron pair reveals a hierarchy of regulation among multiple inputs—sex, age, nutritional status, and microbial environment—which function in the modulation of behavior. Our results suggest that regulation of gene expression in sensory neurons can function in the integration of a wide array of sensory information and facilitate decision-making behaviors in C. elegans.


Development ◽  
1990 ◽  
Vol 108 (1) ◽  
pp. 107-119 ◽  
Author(s):  
R. Schnabel ◽  
H. Schnabel

The early somatic blastomeres founding the tissues in the C. elegans embryo are derived in a stem-cell-like lineage from the P cells. We have isolated maternal effect lethal mutations defining the gene cib-1 in which the P cells, P1-P3, skip a cell cycle and acquire the fates of only their somatic daughters. Therefore, the cib-1 gene is required for the specification of the stem-cell-like fate of these cells. The analysis of the development of these mutants suggests that the clock controlling the cell cycles in the early embryo is directly coupled to the fate of a cell and that there must be another developmental clock that activates the determinative inventory for the early decision-making.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Ping Liu ◽  
Bojun Chen ◽  
Zhao-Wen Wang

Abstract Proper threat-reward decision-making is critical to animal survival. Emerging evidence indicates that the motor system may participate in decision-making but the neural circuit and molecular bases for these functions are little known. We found in C. elegans that GABAergic motor neurons (D-MNs) bias toward the reward behavior in threat-reward decision-making by retrogradely inhibiting a pair of premotor command interneurons, AVA, that control cholinergic motor neurons in the avoidance neural circuit. This function of D-MNs is mediated by a specific ionotropic GABA receptor (UNC-49) in AVA, and depends on electrical coupling between the two AVA interneurons. Our results suggest that AVA are hub neurons where sensory inputs from threat and reward sensory modalities and motor information from D-MNs are integrated. This study demonstrates at single-neuron resolution how motor neurons may help shape threat-reward choice behaviors through interacting with other neurons.


2018 ◽  
Author(s):  
Fernando Calahorro ◽  
Francesca Keefe ◽  
James Dillon ◽  
Lindy Holden-Dye ◽  
Vincent O’Connor

ABSTRACTThe integration of distinct sensory modalities is essential for behavioural decision making. In C. elegans this process is coordinated by neural circuits that integrate sensory cues from the environment to generate an appropriate behaviour at the appropriate output muscles. Food is a multimodal cue that impacts on the microcircuits to modulating feeding and foraging drivers at the level of the pharyngeal and body wall muscle respectively. When food triggers an upregulation in pharyngeal pumping it allows the effective ingestion of food. Here we show that a C. elegans mutant in the single orthologous gene of human neuroligins, nlg-1 are defective in food induced pumping. This is not explained by an inability to sense food, as nlg-1 mutants are not defective in chemotaxis towards bacteria. In addition, we show that neuroligin is widely expressed in the nervous system including AIY, ADE, ALA, URX and HSN neurones. Interestingly, despite the deficit in pharyngeal pumping neuroligin is not expressed within the pharyngeal neuromuscular network, which suggests an extrapharyngeal regulation of this circuit. We resolve electrophysiologically the neuroligin contribution to the pharyngeal circuit by mimicking a food-dependent pumping, and show that the nlg-1 phenotype is similar to mutants impaired in GABAergic and/or glutamatergic signalling. We suggest that neuroligin organizes extrapharyngeal circuits that regulate the pharynx. These observations based on the molecular and cellular determinants of feeding are consistent with the emerging role of neuroligin in discretely impacting functional circuits underpinning complex behaviours.


Author(s):  
N. T. Chartier ◽  
A. Mukherjee ◽  
J. Pfanzelter ◽  
S. Fürthauer ◽  
B. T. Larson ◽  
...  

AbstractOocytes are large and resourceful. During oogenesis some germ cells grow, typically at the expense of others that undergo apoptosis. How germ cells are selected to live or die out of a homogeneous population remains unclear. Here we show that this cell fate decision in C. elegans is mechanical and related to tissue hydraulics. Germ cells become inflated when the pressure inside them is lower than in the common cytoplasmic pool. This condition triggers a hydraulic instability which amplifies volume differences and causes some germ cells to grow and others to shrink. Shrinking germ cells are extruded and die, as we demonstrate by reducing germ cell volumes via thermoviscous pumping. Together, this reveals a robust mechanism of mechanochemical cell fate decision making in the germline.


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