How did nervous systems evolve?

Neurons and synapses did not appear from scratch. Many of the molecular systems that neurons use today - for sensing the environment, communicating between cells, releasing signals, and responding to them - have much deeper evolutionary origins. We want to understand how these ancient cellular mechanisms were assembled, modified, and co-opted during the emergence of neurons and nervous systems, and how they subsequently gave rise to the remarkable diversity of nervous systems found across animals.

Our research spans molecular, cellular, and organismal scales. We investigate the evolutionary origins of neuronal signalling machinery, the emergence of neuron-like cell types and synapses, and the function of unconventional nervous systems that challenge traditional ideas of how neurons should be organised and connected.

We are particularly interested in:

• The deep evolutionary origins of neuronal signalling - how ancient systems for secretion, excitability, cell–cell communication, and sensory signalling became components of neurons and synapses.
• The emergence of neurons and synapses - how pre-existing molecular modules were combined and reorganised into specialised signalling cells and cellular connections.
• The evolution and diversification of nervous systems - how different animal lineages evolved distinct neural architectures, signalling strategies, and ways of processing information.
• What unconventional organisms can reveal about animal biology - using experimentally tractable systems to uncover fundamental principles of cellular organisation, communication, development, and plasticity.

To address these questions, we focus on organisms that provide unique windows into the early evolution of animal cell communication. These include choanoflagellates, the closest living unicellular relatives of animals, and ctenophores (comb jellies), animals with highly distinctive neurons, synapses, and nervous-system architectures.

We combine comparative genomics and protein evolution with experimental approaches to investigate the molecular, cellular, and functional basis of nervous-system evolution.

By comparing cellular systems across these organisms, we aim to uncover how ancient forms of cell communication contributed to the origin of nervous systems - and how evolution has continued to reinvent the ways in which animal cells communicate, connect, and behave.

I am actively involved in communicating science to broad audiences, with a particular focus on the evolution of nervous systems, choanoflagellates & ctenophores, and the origins of animal cell communication.

Our research has received extensive international media coverage, including features in major international outlets such as The New York Times, CNN, BBC, The Guardian, Deutsche Welle, and CBC, as well as leading science publications including National Geographic, Nature, Science, Quanta Magazine, Scientific American, and New Scientist. Recent highlights include the Discover Magazine Summer 2026 cover feature Brainless, as well as international coverage of our work on the syncytial nervous system of ctenophores and reverse development in Mnemiopsis leidyi.

Together with my group, I also engage directly with the public through exhibitions, science festivals, school visits, public talks, and collaborations with museums and aquaria. Activities have included Jellyfish Unveiled at the University Museum of Bergen, as well as collaborations with Bergen Aquarium and Paris Aquarium, where ctenophores from our facility have been displayed to the public.

Our group has also developed a dedicated ORIGINEURO science communication programme, including interactive activities on evolution, nervous systems, and comb jellies for audiences ranging from schoolchildren to the general public.

Explore our science communication and outreach activities

I teach on the following courses at the University of Bergen:

• BIO103 – Cell Biology & Genetics
• BIO210 – Evolutionary Biology
• MOL214 – Molecular Biology of the Nervous System
• MOL213 – Developmental Genetics

Selected publications

A complete publication list is available on Google Scholar and ORCID.

Ferraioli A, Burkhardt P (2026) Evolution: Ancient monoamines in a neuron-less animal. Current Biology 36: R850–R852.

Styfhals R, Burkhardt P (2026) Body-plan organizer in comb jellies hints at animal ancestry. Nature 655: 855–856.

Ferraioli A, Digel L, Sturm D, Colgren J, Le Goff C, Jan A, Soto-Angel JJ, Naumann B, Kittelmann M, Burkhardt P (2026) The 3D architecture of the ctenophore aboral organ and the evolution of complex integrative centers in animals. Science Advances 12: eaea8399.

Colgren JJ, Burkhardt P (2026) The evolutionary origins of synaptic proteins and their changing roles in different organisms across evolution. Nature Reviews Neuroscience 27: 7–22.

Jokura K, Jasek S, Niederhaus L, Burkhardt P, Jékely G (2026) Neural connectome of the ctenophore statocyst. eLife 14: RP108420.

Kim IV, Navarrete C, Grau-Bové X, Iglesias M, Elek A, Zolotarov G, Bykov NS, Montgomery SA, Ksiezopolska E, Cañas-Armenteros D, Soto-Angel JJ, Leys SP, Burkhardt P, Suga H, de Mendoza A, Marti-Renom MA, Sebé-Pedrós A (2025) Chromatin loops are an ancestral hallmark of the animal regulatory genome. Nature 642: 1097–1105.

Colgren J, Burkhardt P (2025) Electrical signaling and coordinated behavior in the closest relative of animals. Science Advances 11: eadr7434.

Soto-Angel JJ, Burkhardt P (2024) Reverse development in the ctenophore Mnemiopsis leidyi. Proceedings of the National Academy of Sciences USA 121: e2411499121.

Burkhardt P, Colgren J, Medhus A, Digel L, Naumann B, Soto-Angel JJ, Nordmann EL, Sachkova MY, Kittelmann M (2023) Syncytial nerve net in a ctenophore adds insights on the evolution of nervous systems. Science 380: 293–297.

Burkhardt P (2022) Ctenophores and the evolutionary origin(s) of neurons. Trends in Neurosciences 45: 878–880.

Gahan JM, Kouzel IU, Jansen KO, Burkhardt P, Rentzsch F (2022) Histone demethylase Lsd1 is required for the differentiation of neural cells in Nematostella vectensis. Nature Communications 13: 465.

Sachkova MY, Nordmann EL, Soto-Angel JJ, Meeda Y, Górski B, Naumann B, Dondorp D, Chatzigeorgiou M, Kittelmann M, Burkhardt P (2021) Neuropeptide repertoire and 3D anatomy of the ctenophore nervous system. Current Biology 31: 5274–5285.

Musser JM, Schippers KJ, Nickel M, Mizzon G, Kohn AB, Pape C, Hammel JU, Wolf F, Liang C, Hernández-Plaza A, Achim K, Schieber NL, Francis WR, Vargas S, Kling S, Renkert M, Feuda R, Gaspar I, Burkhardt P, Bork P, Beck M, Kreshuk A, Wörheide G, Huerta-Cepas J, Schwab Y, Moroz LL, Arendt D (2021) Profiling cellular diversity in sponges informs animal cell type and nervous system evolution. Science 374: 717–723.

Göhde R, Naumann B, Laundon D, Imig C, McDonald K, Cooper BH, Varoqueaux F, Fasshauer D, Burkhardt P (2021) Choanoflagellates and the ancestry of neurosecretory vesicles. Philosophical Transactions of the Royal Society B 376: 20190759.

Burkhardt P, Jékely G (2021) Evolution of synapses and neurotransmitter systems: The divide-and-conquer model for early neural cell-type evolution. Current Opinion in Neurobiology 71: 127–138.

Laundon D, Larson BT, McDonald K, King N, Burkhardt P (2019) The architecture of cell differentiation in choanoflagellates and sponge choanocytes. PLoS Biology 17: e3000226.

Burkhardt P, Grønborg M, McDonald K, Sulur T, Wang Q, King N (2014) Evolutionary insights into premetazoan functions of the neuronal protein Homer. Molecular Biology and Evolution 31: 2342–2355.

Meijer M, Burkhardt P, de Wit H, Toonen RF, Fasshauer D, Verhage M (2012) Munc18-1 mutations that strongly impair SNARE-complex binding support normal synaptic transmission. The EMBO Journal 31: 2156–2168.

Burkhardt P, Stegmann CM, Cooper B, Klöpper TH, Imig C, Varoqueaux F, Wahl MC, Fasshauer D (2011) Primordial neurosecretory apparatus identified in the choanoflagellate Monosiga brevicollis. Proceedings of the National Academy of Sciences USA 108: 15264–15269.

Burkhardt P, Hattendorf DA, Weis WI, Fasshauer D (2008) Munc18 controls SNARE assembly through its interaction with the syntaxin N-peptide. The EMBO Journal 27: 923–933.

ORIGINEURO - Tracking the deep evolutionary origins of neurons

European Research Council (ERC) Consolidator Grant | 2023–2027

ORIGINEURO investigates how neurons and nervous systems emerged during animal evolution. The project combines molecular, cellular and organismal approaches to study the unusual nervous system of ctenophores and the deeper evolutionary origins of neuronal signalling mechanisms. By exploring how nervous systems are built, develop and function in these early-diverging animals, ORIGINEURO aims to uncover fundamental principles underlying the origin and diversification of nervous systems.

Principal Investigator: Pawel Burkhardt
ERC Consolidator Grant, Grant Agreement No. 101044989

Decoding the gelatinous origins of brain evolution

Human Frontier Science Program (HFSP) Research Grant – Program | 2023–2026

How did the first animal brains process information and control behaviour? This interdisciplinary project combines experimental neurobiology with theoretical and computational approaches to investigate neural processing in the ctenophore Mnemiopsis leidyi. By integrating nervous-system anatomy, behaviour, neural activity and computational modelling, the project aims to uncover principles that may have shaped the earliest forms of neural information processing.

Joint project with Fred Wolf, University of Göttingen / Max Planck Institute for Dynamics and Self-Organization
HFSP Research Grant – Program, RGP025/2023