NiCE: The neural control of larval settlement in a genetically tractable jellyfish

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

The lifecycle of many marine organisms includes a free-swimming larval stage that searches for a place to attach, where it metamorphoses into an adult. This search and decision-making process (larval settlement) is poorly understood yet essential: it is expected to play critical roles in determining species density and to be point of vulnerability. Understanding larval settlement therefore has important societal implications for both promoting the growth of desired species and protecting regions from invasive species and biofouling. Despite the importance of this process, remarkably little is known of the underlying neural mechanisms. Using larvae from the jellyfish Clytia as a model, this work will perform a systematic study of the neural control of settlement. This deeper understanding could be foundational for developing new solutions for prediction and manipulation of the density of critical marine organisms for the betterment of human society and ocean health. In addition to these scientific impacts, integral to this proposed work is training the next generation of scientists. Clytia make an exceptional research organism for undergraduate research: it is easy and low-cost for students to gain hands-on research experience using Clytia, and this work will expose numerous undergraduates to research experience. Lastly, a goal of this work is for Clytia to become a widely used model organism for neuroscience research. This work will be foundational for bolstering a Clytia community asking fundamental questions in neural evolution, development, regeneration, and the neural control of behavior. The tools and approaches developed here are also expected to be readily applied to other species. Together, the impacts of this work are expected to go beyond the scientific research to include education, outreach, bolstering a broader scientific community, and other benefits to society. The technical approach to study the neural control of settlement proposed here is to leverage modern optical and genetic tools to ask: what is the logic that larvae use to explore their environments and how is this logic implemented in neural systems? Genetic tools have been established in Clytia, and this proposal applies a suite of modern neuroscience tools for behavioral analysis, imaging neural activity, and ablating specific neural cell types. In Aim 1, this proposal will apply automated behavioral tracking and modelling to delineate the strategy employed by larvae as they search for and choose a location to settle; it will then ask how these behaviors are impacted by environmental stressors. In Aim 2, this proposal will record from the entire larval nervous system to ask how sensory processing and decision-making are implemented in population neural activity. It will then examine which aspects of neural processing are vulnerable/resilient to perturbation. Lastly, in Aim 3, this proposal will examine the causal contributions of neural subnetworks through loss-of-function experiments. Together, this work is expected to contribute foundational insights into the neural control of behavior in these critically important marine organisms and to reveal aspects of their neurobiology that confer vulnerability or resistance in response to perturbation. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.