S9  Revealing the evolutionary trajectory of the first nervous systems: genomics, structure and dynamics

Pawel Burkhardt (Bergen, Norway) and Fred Wolf (Göttingen)

Live Discussion: Tuesday, March 23, 2021, 18:00 - 19:00h

Neurons are the building blocks of nervous systems and of information processing in the brain. While the molecular mechanisms of neuronal communication are largely known, our understanding of when, how and why neurons and synapses originated in animal evolution still is very limited. Key to uncovering the evolutionary origin of neurons and synapses is the controversy on the relationships at the base of animal phylogeny. The four non-bilaterian animal phyla include organisms with no recognizable nerve cells, sponges and placozoans, as well as organisms with clearly recognizable nerve cells, ctenophores and cnidarians. Although still under intense scrutiny the differences in neuronal processing between ctenophores and cnidarians implicate that synaptic transmission may have evolved more than once.
This symposium will highlight emerging research and discuss future research directions in revealing early nervous system evolution. Leading experts and pioneers in the study of the earliest branching animal lineages will present a wide range of approaches. Elizabeth Amy Williams will introduce the placozoan Trichoplax adhaerens and show how complex neuropeptidergic signaling controls a rich repertoire of behavior in this nerve-less animal. Mari-Luz Hernandez Nicaise will present work on the unique nervous system found in ctenophores which most likely evolved independently in this lineage. Christophe Dupre pioneered calcium imaging in cnidarians to simultaneously monitor behavior, neuronal and muscle activity in the behaving animal and Raoul-Martin Memmesheimer uses modeling to examine how early neurons communicate with each other to organize swimming behavior. Young investigator talks by Han Chen and Xitong Liang will highlight an exotic system of Ca2+ dependent exocytosis recruited in specialized mammalian synapses and the evolutionary divergence of high dimensional motor systems in lophotrochozoa respectively. Together these studies provide intriguing novel perspectives on the very origin and deep history of the cells and organs that harbor the animal mind.
This event is supported by the DFG Priority Program 2205 “Evolutionary Optimization of Neuronal Processing”.

S9-1 Mari-Luz Hernandez Nicaise, Nice, France
The ctenophore nervous system: from Hertwig hand drawings to genetic studies, what do we really know?

S9-2 Elizabeth Amy Williams, Exeter, United Kingdom
Placozoan behaviour is coordinated by neuropeptide-like signaling.

S9-3 Han Chen, Göttingen, Germany
Testing the Ca2+sensor hypothesis of otoferlin

S9-4 Raoul-Martin Memmesheimer, Bonn, Germany
From Single Neurons to Behavior in the Jellyfish Aurelia aurita

S9-5 Xitong Liang, Frankfurt am Main, Germany
Neural control of 2-d skin patterning in two species of cephalopods

S9-6 Christophe Dupre, Cambridge, USA
Scalability in the nervous system of Hydra