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Event Details

  • Tuesday, April 10, 2018
  • 18:15 - 18:30

Eloise de Tredern - A glial involvement at the somatic level during long term memory consolidation in Drosophila melanogaster

High level cognitive tasks such as long-term memory formation require transcriptional regulations and de novo protein synthesis in the soma. Still, in this compartment, it is unknown if and how neuronal metabolism is regulated and sustained by glia, as it is well demonstrated at the level of the axon and the synapse (Bélanger et al., Cell Metabolism, 2011). In the model organism Drosophila melanogaster, five glial subtypes populate the central nervous system (Kremer et al., Glia, 2017). The brain is enclosed inside the equivalent of the brain-blood barrier, composed by perineurial and subperineurial glia. Axons and dendrites – the neuropil - are localized at the centre of the brain, while neuronal somas are segregated at the periphery. Astrocyte-like glia extend multiple processes deep into the neuropil, while ensheathing glia enwrap neuropil structures. In the periphery of the brain, cortex glial cells envelop each neuronal soma individually. Thanks to the diverse and precise genetic tools available in this model, we expressed the dominant thermosensitive allele of dynamin specifically in these different glial subtypes. By transferring flies at restrictive temperature, it allowed us to block exocytosis in the targeted glial cells in a spatiotemporally defined window. Using this approach, we showed that cortex glial cells were involved very early in olfactory memory formation, and specifically in long-term memory. Mushroom bodies are the integrative structures involved in associative memory in the fly brain. We now study if cortex glia could be activated by a signal derived from mushroom-body neurons, which are cholinergic (Barnstedt et al., Neuron, 2016). Data from feeding experiments indirectly suggest that, once activated, cortex glia would support neuronal cell bodies metabolism, but the pathways involved still need to be more precisely deciphered.