Biology subjects

Ringstad, N.

Publications and source records attributed to Ringstad, N..

5 recordsLinked to original sources

bioRxiv2026

A stereotyped glial attachment determines the morphology and function of neuronal cilia

Primary cilia are signaling hubs that influence nearly every aspect of cell physiology. Neuronal primary cilia were recently discovered to interact with glia in the mammalian brain, but how cilia-glia attachments form and what roles they play remain unknown. Here, we find that two C. elegans sensory neurons (URX and BAG) use their primary cilia to attach to a specific glial partner (ILsoL). Through a genetic screen, we find that cilia-glia attachment requires BUG-1, a secreted protein with conserved cell adhesion domains that localizes to the cilia-glia attachment site. In the absence of BUG-1, neuronal cilia are present but fail to attach to the glial cell. We find that loss of cilia-glia attachment alters cilia morphology and disrupts stimulus-evoked calcium dynamics in cilia. We propose that primary cilia not only act as antennae for long-range cell communication, but also form close-range cell attachments that modulate cell signaling.

developmental biology↗

bioRxiv2024

Compressed sensing based approach identifies modular neural circuitry driving learned pathogen avoidance

An animals survival hinges on its ability to integrate past information to modify future behavior. The nematode C. elegans adapts its behavior based on prior experiences with pathogen exposure, transitioning from attraction to avoidance of the pathogen. A systematic screen for the neural circuits that integrate the information of previous pathogen exposure to modify behavior has not been feasible because of the lack of tools for neuron type specific perturbations. We overcame this challenge using methods based on compressed sensing to efficiently determine the roles of individual neuron types in learned avoidance behavior. Our screen revealed that distinct sets of neurons drive exit from lawns of pathogenic bacteria and prevent lawn re-entry. Using calcium imaging of freely behaving animals and optogenetic perturbations, we determined the neural dynamics that regulate one key behavioral transition after infection: stalled re-entry into bacterial lawns. We find that key neuron types govern pathogen lawn specific stalling but allow the animal to enter nonpathogenic E. coli lawns. Our study shows that learned pathogen avoidance requires coordinated transitions in discrete neural circuits and reveals the modular structure of this complex adaptive behavioral response to infection.

neuroscience↗

bioRxiv2023

Scalable Apparatus to Measure Posture and Locomotion (SAMPL): a high-throughput solution to study unconstrained vertical behavior in small animals

Balance and movement are impaired in a wide variety of neurological disorders. Recent advances in behavioral monitoring provide unprecedented access to posture and loco-motor kinematics, but without the throughput and scalability necessary to screen candidate genes / potential therapeutics. We present a powerful solution: a Scalable Apparatus to Measure Posture and Locomotion (SAMPL). SAMPL includes extensible imaging hardware and low-cost open-source acquisition software with real-time processing. We first demonstrate that SAMPLs hardware and acquisition software can acquire data from D. melanogaster, C.elegans, and D. rerio as they move vertically. Next, we leverage SAMPLs throughput to rapidly (two weeks) gather a new zebrafish dataset. We use SAMPLs analysis and visualization tools to replicate and extend our current understanding of how zebrafish balance as they navigate through a vertical environment. Next, we discover (1) that key kinematic parameters vary systematically with genetic background, and (2) that such background variation is small relative to the changes that accompany early development. Finally, we simulate SAMPLs ability to resolve differences in posture or vertical navigation as a function of effect size and data gathered - key data for screens. Taken together, our apparatus, data, and analysis provide a powerful solution for laboratories using small animals to investigate balance and locomotor disorders at scale. More broadly, SAMPL is both an adaptable resource for laboratories looking process video-graphic measures of behavior in real-time, and an exemplar of how to scale hardware to enable the throughput necessary for screening.

neuroscience↗

bioRxiv2021

Opponent vesicular transporters regulate the strength of glutamatergic neurotransmission in a C. elegans sensory circuit

At chemical synapses, neurotransmitters are packaged into synaptic vesicles that release their contents in response to depolarization. Despite its central role in synaptic function, regulation of the machinery that loads vesicles with neurotransmitters remains poorly understood. We find that synaptic glutamate signaling in a C. elegans chemosensory circuit is regulated by antagonistic interactions between the canonical vesicular glutamate transporter EAT-4/VGLUT and another vesicular transporter, VST-1. Loss of VST-1 strongly potentiates glutamate release from chemosensory BAG neurons and disrupts chemotaxis behavior. Analysis of the circuitry downstream of BAG neurons shows that excess glutamate release disrupts behavior by inappropriately recruiting RIA interneurons to the BAG-associated chemotaxis circuit. Our data indicate that in vivo the strength of glutamatergic synapses is controlled by regulation of neurotransmitter packaging into synaptic vesicles via functional coupling of VGLUT and VST-1.

neuroscience↗

bioRxiv2018

Repression of an activity-dependent autocrine insulin signal is required for sensory neuron development in C. elegans.

Nervous system development is instructed both by genetic programs and activity-dependent refinement of gene expression and connectivity. How these mechanisms are integrated remains poorly understood. Here, we report that the regulated release of insulin-like peptides (ILPs) during development of the C. elegans nervous system accomplishes such an integration. We find that the p38 MAP kinase PMK-3, which is required for the differentiation of chemosensory BAG neurons, functions by limiting expression of an autocrine ILP signal that represses a chemosensory-neuron fate. ILPs are released from BAGs in an activity-dependent manner during embryonic development, and regulate neurodifferentiation through a non-canonical insulin receptor signaling pathway. The differentiation of a specialized neuron-type is, therefore, coordinately regulated by a genetic program that controls ILP expression and by neural activity, which regulates ILP release. Autocrine signals of this kind may have general and conserved functions as integrators of deterministic genetic programs with activity-dependent mechanisms during neurodevelopment.

neuroscience↗