Juvenile hormone drives the maturation of spontaneous mushroom body neural activity and learned behavior.

Mature behaviors emerge from neural circuits sculpted by genetic programs and spontaneous and evoked neural activity. However, how neural activity is refined to drive maturation of learned behavior remains poorly understood. Here, we explore how transient hormonal signaling coordinates a neural activity state transition and maturation of associative learning.

Predator-secreted sulfolipids induce defensive responses in C. elegans.

Animals respond to predators by altering their behavior and physiological states, but the underlying signaling mechanisms are poorly understood. Using the interactions between Caenorhabditis elegans and its predator, Pristionchus pacificus, we show that neuronal perception by C. elegans of a predator-specific molecular signature induces instantaneous escape behavior and a prolonged reduction in oviposition.

Circuit mechanisms encoding odors and driving aging-associated behavioral declines in Caenorhabditis elegans.

Chemosensory neurons extract information about chemical cues from the environment. How is the activity in these sensory neurons transformed into behavior? Using Caenorhabditis elegans, we map a novel sensory neuron circuit motif that encodes odor concentration. Primary neurons, AWC(ON) and AWA, directly detect the food odor benzaldehyde (BZ) and release insulin-like peptides and acetylcholine, respectively, which are required for odor-evoked responses in secondary neurons, ASEL and AWB.

From genes to circuits and behaviors: Neuropeptides expand the coding potential of the nervous system.

Neuropeptide signaling remodels the composition of a chemosensory circuit and shapes behavior in Caenorhabditis elegans. We reported that the ASE left (ASEL) salt sensory neuron uses a proprotein convertase, BLI-4, to cleave the insulin-like peptide INS-6. INS-6 peptides are released from the ASEL neuron in response to large, but not small changes in salt stimuli.

Neuropeptide signaling remodels chemosensory circuit composition in Caenorhabditis elegans.

Neural circuits detect environmental changes and drive behavior. The routes of information flow through dense neural networks are dynamic, but the mechanisms underlying this circuit flexibility are poorly understood. Here, we define a sensory context-dependent and neuropeptide-regulated switch in the composition of a C.

Olfactory networks: from sensation to perception.

Olfactory networks, comprised of sensory neurons and interneurons, detect and process changes in the chemical environment to drive animal behavior. Recent studies combining genetics with behavioral analyses and imaging in worms, flies and mice have revealed new insights into the mechanisms of olfaction. In this discussion, we focus on three interesting findings.

The calmodulin-stimulated adenylate cyclase ADCY8 sets the sensitivity of zebrafish retinal axons to midline repellents and is required for normal midline crossing.

The chemokine SDF1 activates a cAMP-mediated signaling pathway that antagonizes retinal responses to the midline repellent slit. We show that knocking down the calmodulin-activated adenylate cyclase ADCY8 makes retinal axons insensitive to SDF1. Experiments in vivo using male and female zebrafish (Danio rerio) confirm a mutual antagonism between slit signaling and ADCY8-mediated signaling.