A PhD student stipend is available starting 2015. The goal is to reveal how rapid changes of astrocyte gap junction coupling modify hippocampal network function. More information can be found here. Application deadline is the 11th of January.
The structure of astrocytes is likely to shape the interaction between neurons and astrocytes in the brain. It is intuitive that astrocytes processes close to a synapse can more effectively modify synapse function than distant processes. Mike Stewart’s lab at Milton Keynes has now demonstrated in collaboration with us that astrocyte processes cover thin neuronal spines receiving excitatory input more than bigger spines, so called mushroom spines (Phil. Trans. R. Soc. B, link). This is of particular interest because thin spines are widely believed to represent spines at which long-term potentiation (LTP, the potential cellular mechanism of learning) has not occurred yet. It might suggest that these spines are particularly well protected from spill-in of neurotransmitter from neighboring synapses.
In a separate study we were wondering if morphology of whole astrocytes is heterogeneous within a brain region. Using fluorescence imaging in brain slices we could reveal that brain regions occupied by individual astrocytes can be oriented along principal cell dendrites (hippocampus, CA1 region). A subset of these cells had a morphology that could promote intracellular diffusion along along principal cell dendrites. Indeed astrocyte coupling, a key feature of astrocyte networks, was anisotropic and more pronounced along the same axis (Phil. Trans. R. Soc. B., link). These observations imply that astrocyte morphology determines spread of a diffusible signal within a gap junction coupled astrocyte network and can give it a directionality.
… and of course congratulations to all authors.
Congratulations to Alistair Jennings who passed his viva on the 1st of August. In his work he characterized how hippocampal astrocytes respond to dopamine and identified the signalling cascades involved in generating the astrocyte Ca2+ response. Congratulations Dr Jennings! 🙂
DFG project grant awarded to study the “Heterogeneity of astrocyte morphology as a determinant of synaptic release” in the context of the priority program (SPP1757). The general goal of project is to reveal how astrocyte morphology and its changes modify function of synaptic terminals in the hippocampus.
Our collaborators Colin Jackson and Jason Whitfield (ANU, Canberra, Australien) joined us for a few weeks of experiments on novel optical sensors for in situ measurements of arginine in brain tissue.