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SUMMARY:On chemical and synaptic brains and the evolution of nervous syste
 ms - Prof Gaspar Jékely
DTSTART:20220511T120000Z
DTEND:20220511T130000Z
UID:TALK172259@talks.cam.ac.uk
CONTACT:Giacomo Gattoni
DESCRIPTION:In nervous systems\, there are two main modes of transmission 
 for the propagation of activity between cells. Synaptic transmission relie
 s on close contact at chemical or electrical synapses while volume transmi
 ssion is mediated by diffusible chemicals and does not require direct cont
 act. In principle\, it is possible to wire arbitrarily complex neuronal ne
 tworks by both chemical and synaptic transmission. Both types of networks 
 are ubiquitous in nervous systems\, leading to the question which of the t
 wo appeared first in evolution. Last year\, I proposed a scenario where ch
 emically organized cellular networks appeared before synapses in evolution
 . This was supported by the presence of complex peptidergic signalling in 
 all animals except sponges. More recently\, we have discovered the first n
 europeptide-like molecules in sponges and choanoflagellates\, giving more 
 support to this chemical brain hypothesis. We also carried out large-scale
  pharmacological screens and identified several cnidarian and placozoan ne
 uropeptide receptors\, indicating extensive peptidergic transmission in th
 ese non-bilaterian animals. In our work on the larval neurosecretory cente
 r of the annelid Platynereis\, we are experimentally investigating how syn
 aptic and chemical networks interact. We have reconstructed the full synap
 tic connectome of the Platynereis larva and densely mapped neuromodulators
  to the connectome. Through calcium imaging\, CRISPR knockouts and behavio
 ural work we aim to understand how the chemical and the synaptic brain wor
 k together to generate circuit activity during behaviour.
LOCATION:Part II Lecture Theatre\, Department of Zoology
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