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Séminaire impromptu - Arne BattefeldFunctional aspects of grey matter oligodendrocyte-neuron interaction / Candidat à une chaire Bx Neurocampus

Abstract :

 The name white matter stems from the lipid rich myelin layers produced by oligodendrocytes, however, substantial numbers of oligodendrocytes can be found in the neocortical grey matter.
Besides increase of propagation speed, myelin has been shown to play other important roles in e.g. brain energy homeostasis. Using the anatomical arrangement of the grey matter as basis for our experimental approach, we investigated the physiological interaction between neurons and oligodendrocytes. Here, we demonstrated that so called grey matter satellite oligodendrocytes participate in potassium uptake during neuronal firing.

By using electrophysiological approaches, we found that satellite oligodendrocytes integrate into an astroglial syncytium that modulated neuronal excitability. As myelin plasticity in response to neuronal activity has been established, but the exact mechanisms are unknown, we further investigated the modulation of oligodendrocytes on the single axon level. Using a fast and high-sensitivity imaging approach we investigated oligodendrocytic calcium dynamics in response to evoked action potentials on identified axon-myelin assemblies.
These latter experiments suggest that oligodendrocytic calcium dynamics are important for lateral and radial myelin remodelling and appear independent of neuronal firing.