Aberrant Positions of the Chemosensory Neurons in the Neurotransmitter-Release Mutant .

Secretion of neurotransmitter- and neuropeptide-containing vesicles is a regulated process orchestrated by multiple proteins. Of these, mutants, defective in the and genes, responsible for neurotransmitter and neuropeptide release, respectively, are routinely used to elucidate neural and circuitry functions. While these mutants result in severe functional deficits, their neuroanatomy is assumed to be intact.

Intricate response dynamics enhances stimulus discrimination in the resource-limited C. elegans chemosensory system.

Background: Sensory systems evolved intricate designs to accurately encode perplexing environments. However, this encoding task may become particularly challenging for animals harboring a small number of sensory neurons. Here, we studied how the compact resource-limited chemosensory system of Caenorhabditis elegans uniquely encodes a range of chemical stimuli.

Inheritance of associative memories and acquired cellular changes in C. elegans.

Experiences have been shown to modulate behavior and physiology of future generations in some contexts, but there is limited evidence for inheritance of associative memory in different species. Here, we trained C. elegans nematodes to associate an attractive odorant with stressful starvation conditions and revealed that this associative memory was transmitted to the F1 progeny who showed odor-evoked avoidance behavior.

Principles for coding associative memories in a compact neural network.

A major goal in neuroscience is to elucidate the principles by which memories are stored in a neural network. Here, we have systematically studied how four types of associative memories (short- and long-term memories, each as positive and negative associations) are encoded within the compact neural network of worms. Interestingly, sensory neurons were primarily involved in coding short-term, but not long-term, memories, and individual sensory neurons could be assigned to coding either the conditioned stimulus or the experience valence (or both).

The synaptic organization in the neural network suggests significant local compartmentalized computations.

Neurons are characterized by elaborate tree-like dendritic structures that support local computations by integrating multiple inputs from upstream presynaptic neurons. It is less clear whether simple neurons, consisting of a few or even a single neurite, may perform local computations as well. To address this question, we focused on the compact neural network of  animals for which the full wiring diagram is available, including the coordinates of individual synapses.

A negative feedback loop in the GPCR pathway underlies efficient coding of external stimuli.

Efficient navigation based on chemical cues is an essential feature shared by all animals. These cues may be encountered in complex spatiotemporal patterns and with orders of magnitude varying intensities. Nevertheless, sensory neurons accurately extract the relevant information from such perplexing signals.

A Fusion PCR Method for Expressing Genetic Tools in C. elegans.

C. elegans offer a unique opportunity for understanding computation in neural networks. This is largely due to their relatively compact neural network for which a wiring diagram is available.

Dopamine-dependent biphasic behaviour under 'deep diving' conditions in .

Underwater divers are susceptible to neurological risks due to their exposure to increased pressure. Absorption of elevated partial pressure of inert gases such as helium and nitrogen may lead to nitrogen narcosis. Although the symptoms of nitrogen narcosis are known, the molecular mechanisms underlying these symptoms have not been elucidated.

Author Correction: Concerted pulsatile and graded neural dynamics enables efficient chemotaxis in C. elegans.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Addendum: Irrational behavior in C. elegans arises from asymmetric modulatory effects within single sensory neurons.

We would like to make our readers aware of the publication by Cohen et al., which reports irrational behaviour in C. elegans olfactory preference[1] .

Irrational behavior in C. elegans arises from asymmetric modulatory effects within single sensory neurons.

C. elegans worms exhibit a natural chemotaxis towards food cues. This provides a potential platform to study the interactions between stimulus valence and innate behavioral preferences.

A Memory Circuit for Coping with Impending Adversity.

Organisms' capacity to anticipate future conditions is key for survival. Associative memories are instrumental for learning from past experiences, yet little is known about the processes that follow memory retrieval and their potential advantage in preparing for impending developments. Here, using C.

Concerted pulsatile and graded neural dynamics enables efficient chemotaxis in C. elegans.

The ability of animals to effectively locate and navigate toward food sources is central for survival. Here, using C. elegans nematodes, we reveal the neural mechanism underlying efficient navigation in chemical gradients.

Salient experiences are represented by unique transcriptional signatures in the mouse brain.

It is well established that inducible transcription is essential for the consolidation of salient experiences into long-term memory. However, whether inducible transcription relays information about the identity and affective attributes of the experience being encoded, has not been explored. To this end, we analyzed transcription induced by a variety of rewarding and aversive experiences, across multiple brain regions.

A multi-animal tracker for studying complex behaviors.

Background: Animals exhibit astonishingly complex behaviors. Studying the subtle features of these behaviors requires quantitative, high-throughput, and accurate systems that can cope with the often rich perplexing data.

Results: Here, we present a Multi-Animal Tracker (MAT) that provides a user-friendly, end-to-end solution for imaging, tracking, and analyzing complex behaviors of multiple animals simultaneously.

The C. elegans Connectome Consists of Homogenous Circuits with Defined Functional Roles.

A major goal of systems neuroscience is to decipher the structure-function relationship in neural networks. Here we study network functionality in light of the common-neighbor-rule (CNR) in which a pair of neurons is more likely to be connected the more common neighbors it shares. Focusing on the fully-mapped neural network of C.

Serotonin promotes exploitation in complex environments by accelerating decision-making.

Background: Fast responses can provide a competitive advantage when resources are inhomogeneously distributed. The nematode Caenorhabditis elegans was shown to modulate locomotion on a lawn of bacterial food in serotonin (5-HT)-dependent manners. However, potential roles for serotonergic signaling in responding to food discovery are poorly understood.

A Fusion PCR Method for Expressing Genetic Tools in C. elegans.

C. elegans offer a unique opportunity for understanding computation in neural networks. This is largely due to their relatively compact neural network for which a wiring diagram is available.

Hierarchical sparse coding in the sensory system of Caenorhabditis elegans.

Animals with compact sensory systems face an encoding problem where a small number of sensory neurons are required to encode information about its surrounding complex environment. Using Caenorhabditis elegans worms as a model, we ask how chemical stimuli are encoded by a small and highly connected sensory system. We first generated a comprehensive library of transgenic worms where each animal expresses a genetically encoded calcium indicator in individual sensory neurons.

The response to high CO2 levels requires the neuropeptide secretion component HID-1 to promote pumping inhibition.

Carbon dioxide (CO2) is a key molecule in many biological processes; however, mechanisms by which organisms sense and respond to high CO2 levels remain largely unknown. Here we report that acute CO2 exposure leads to a rapid cessation in the contraction of the pharynx muscles in Caenorhabditis elegans. To uncover the molecular mechanisms underlying this response, we performed a forward genetic screen and found that hid-1, a key component in neuropeptide signaling, regulates this inhibition in muscle contraction.

Measuring the effects of high CO₂ levels in Caenorhabditis elegans.

Carbon dioxide (CO2) is an important molecule in cell metabolism. It is also a byproduct of many physiological processes. In humans, impaired lung function and lung diseases disrupt the body's ability to dispose of CO2 and elevate its levels in the body (hypercapnia).

A genome-wide analysis of promoter-mediated phenotypic noise in Escherichia coli.

Gene expression is subject to random perturbations that lead to fluctuations in the rate of protein production. As a consequence, for any given protein, genetically identical organisms living in a constant environment will contain different amounts of that particular protein, resulting in different phenotypes. This phenomenon is known as "phenotypic noise.

A modular library of small molecule signals regulates social behaviors in Caenorhabditis elegans.

The nematode C. elegans is an important model for the study of social behaviors. Recent investigations have shown that a family of small molecule signals, the ascarosides, controls population density sensing and mating behavior.

Metazoan operons accelerate recovery from growth-arrested states.

Existing theories explain why operons are advantageous in prokaryotes, but their occurrence in metazoans is an enigma. Nematode operon genes, typically consisting of growth genes, are significantly upregulated during recovery from growth-arrested states. This expression pattern is anticorrelated to nonoperon genes, consistent with a competition for transcriptional resources.

Cost of unneeded proteins in E. coli is reduced after several generations in exponential growth.

When E. coli cells express unneeded protein, they grow more slowly. Such penalty to fitness associated with making proteins is called protein cost.