We study the assembly and function of neural systems from an evolutionary-comparative perspective. Broadly, we are interested in the extent to which diverse nervous systems share common principles, and when they do – why? We are equally interested in discovering biological novelty and more broadly understanding the options for nervous system design and function, including why some nervous systems are more robust and regenerative than others. Our approach is to use a new neuroscience model: the tiny (1mm-1cm), transparent jellyfish, Clytia. We established genetic tools in Clytia, making them the only genetically tractable jellyfish. Clytia are of the earliest branching outgroup to principal neuroscience models after a common origin of neurons, making them a critical point of comparison, including for inferences about nervous system origins. Clytia also have a number of remarkable features to examine and compare across species: specifically, their ability to scale their nervous system orders of magnitude without disrupting its function and to regenerate entire genetically ablated neural subnetworks. Lastly, we are also interested in applying these tools and perspectives to understand vulnerabilities and/or robustness of the Clytia nervous system to ecologically relevant perturbations. With the new tools that are now available, there is much to discover using these fascinating creatures!
Systems neuroscience
We use diverse approaches to understand the neural basis of behavior, with particular interests in: (1) how animal behavior is modulated by the internal state of the organism over time, (2) how these states - and switches between them - are implemented, (3) how distinct regions and subnetworks of nervous systems communicate & coordinate to give concerted behavioral output, and (4) the roles of neuromodulation in these processes. As Clytia are tiny (1mm-1cm) and transparent, we use optical approaches to examine and perturb the whole nervous system in awake, behaving animals.
Quantitative behavioral analysis
The shape of a single swimming pulse shown by tracking keypoints on the bell
Whole system activity patterns
Neural activity (GCaMP) of a subnetwork of neurons (~10% of total). 40x playback speed.
Anatomy and network structure
Transgenic labelling of neurons that express the neuropeptide RFamide
Molecular and cellular basis
Atlas of cell types from single-cell RNA-sequencing of whole jellyfish
Nervous System Evolution
From a evolutionary perspective, we are interested in: (1) the origins and early evolution of nervous systems, (2) identifying principles and innovations in neural systems across phylogeny, and (3) understanding the co-evolution of neural, morphological, and behavioral novelty. Through comparisons across the Clytia life cycle and with other organisms, Clytia present exceptional opportunities to address these questions.
As a cnidarian, Clytia is an outgroup to the major models in neuroscience, branching after the evolution of neurons (left). They have a 3-staged lifecycle with distinct morphology and behavior at each life stage (right).
Clytia have homologous neurons to our own, but a dramatically different body plan and nervous system organization
Neural Development and Regeneration
Clytia are constantly integrating newborn neurons into their nervous system without disrupting network function, and have incredible abilities to heal and regenerate, including recovery of genetically ablated neurons. We aim to understand these remarkable capabilities at their interface with network function (above).
Constant neurogenesis
Proliferating cells (magenta) located at the base
of each tentacle
Continual migration and wiring
Nerve net neurons (magenta) and muscle (green)
Integration into the network
Activity in the RFamide+ nerve net