Author Archives: chrhe74

Another PhD student position available

Another position for a PhD student is available. It is part of a larger effort to understand how neuronal and synaptic function are dynamically controlled by astrocytes in the hippocampus. The position is advertised on the FENS job market (https://www.fens.org/careers/job-market/job/120099). All details regarding the position, the project and how to apply can be found there.

In the planned research, we will explore how rapid morphological changes of perisynaptic astrocyte processes (see papers below) affect the function and plasticity of nearby excitatory synapses.

Anders, B. Breithausen, P. Unichenko, M.K. Herde, D. Minge, A. Abramian, C. Behringer, T. Deshpande, A. Boehlen, C. Domingos, L. Henning, J. Pitsch, Y.-B. Kim, P. Bedner, C. Steinhäuser, C. Henneberger (2024) Epileptic activity triggers rapid ROCK1-dependent astrocyte morphology changes. Glia 72(3):643-659. (link)

Henneberger C, Bard L, Panatier A, Reynolds J, Kopach O, Medvedev NI, Minge D, Herde MK, Anders S, Kraev I, Heller JP, Rama S, Zheng K, Jensen TP, Sanchez-Romero I, Jackson C, Janovjak H, Ottersen OP, Nagelhus EA, Oliet SHR, Stewart MG, Nägerl UV, Rusakov DA (2020) LTP induction boosts glutamate spillover by driving withdrawal of perisynaptic astroglia. Neuron 108(5):919-936. (link)

PhD studentship available

A neuroscience PhD studentship is available in our lab. The position is part of a larger effort to understand how the plasticity of excitatory synapses is controlled by co-agonists of the N-methyl-D-aspartate receptor (NMDARs). We explore how neurons and non-neuronal cells shape synaptic plasticity, and in turn learning, by supplying the NMDAR co-agonists D-serine and glycine. We do so using newly designed optical indicators for D-serine and glycine. Specifically, we plan to optimize the current generation of optical indicators to study D-serine and glycine signaling in the rodent hippocampus. This will be achieved by using state-of-the-art optical and electrophysiological methods such as intensity and lifetime based multiphoton fluorescence microscopy of genetically encoded and organic indicators.

Please see job advertisement for further details and how to apply. The application deadline is the 3rd of March 2024.

The project is building on the following two papers from our lab (among others):

  • K. Bohmbach, N. Masala, E.M. Schönhense, K. Hill, A.N. Haubrich, A. Zimmer, T. Opitz, H. Beck, C. Henneberger (2022) An astrocytic signaling loop for frequency-dependent control of dendritic integration and spatial learning. Nat. Commun. 13(1):7932. (link, open access)
  • Zhang WH, Herde MK, Mitchell JA, Whitfield JH, Wulff AB, Vongsouthi V, Sanchez-Romero I, Gulakova PE, Minge D, Breithausen B, Schoch S, Janovjak H, Jackson CJ, Henneberger C (2018) Monitoring hippocampal glycine with the computationally designed optical sensor GlyFS. Nat. Chem. Biol. 14(9):861-869. (link)

An astrocytic signaling loop for frequency-dependent control of dendritic integration and spatial learning

It is known that dendrites of hippocampal pyramidal cells amplify clustered glutamatergic input. This involves N-methyl-D-aspartate receptors (NMDARs), whose activity also depends on the presence of NMDAR co-agonists such as D-serine.

In our recent study by Bohmbach et al., we discovered an unexpected frequency-dependent excitatory feedback loop between pyramidal cell activity and dendritic amplification of synaptic input. It is mediated by NMDAR co-agonists and astrocytes. Importantly, disrupting this feedback loop at the level of astrocytes impairs spatial memory.

K. Bohmbach, N. Masala, E.M. Schönhense, K. Hill, A.N. Haubrich, A. Zimmer, T. Opitz, H. Beck, C. Henneberger (2022) An astrocytic signaling loop for frequency-dependent control of dendritic integration and spatial learning. Nat. Commun. 13(1):7932. (link)

PhD student position available

A neuroscience PhD studentship is available. It is part of a larger effort to understand how structural plasticity and turnover of synapses and remodelling of nearby astrocytes are coordinated and what their role for synapse and circuit function and behaviour is.

The specific aim is to reveal the relationship between synaptic structural plasticity and turnover and the remodelling of perisynaptic astrocytic processes in vivo, and to identify the relevant signalling cascades and the consequences of their disruption. The project relies on an extensive experimental toolset for monitoring synaptic and astrocytic structure and its dynamic changes using multiphoton fluorescence microscopy and for manipulating astrocyte morphology.

Please see job advertisement for further details and how to apply. The application deadline is the 31st of March.

The project is building on two recent papers from our lab:

  • Herde K, Bohmbach K, Domingos C, Vana N, Komorowska-Müller JA, Passlick S,  Schwarz I, Jackson CJ, Dietrich D, Schwarz MK, Henneberger C (2020) Local efficacy of glutamate uptake decreases with synapse size. Cell Rep. 32(12):108182 (link, open access)
  • Henneberger C, Bard L, Panatier A, Reynolds J, Kopach O, Medvedev NI, Minge D, Herde MK, Anders S, Kraev I, Heller JP, Rama S, Zheng K, Jensen TP, Sanchez-Romero I, Jackson C, Janovjak H, Ottersen OP, Nagelhus EA, Oliet SHR, Stewart MG, Nägerl UV, Rusakov DA (2020) LTP induction boosts glutamate spillover by driving withdrawal of perisynaptic astroglia. Neuron (in press) (link, open access)

Congratulations and no bye-bye

Congratulations to Kirsten for defending her PhD thesis today. The final verdict after her defense was summa cum laude. Fully deserved, great work!

Again, the defense had to happen entirely online so there was only a very short and adequately socially distanced ceremony. But there will be a time for celebrating more extensively!

Fortunately for us, Kirsten is going to stay with us as a postdoctoral researcher.

Congratulations and bye-bye

Congratulations to Björn for the great defense of his PhD thesis today. The final verdict after his defense, which unfortunately had to happen entirely online, was a fully-deserved summa cum laude. Great work!

Unfortunately for us, Börn has already moved on and is now working as a patent agent. … where he is probably using his experience from our journal clubs to explain each and everyone why there is absolutely nothing new about their recent inventions.

European University NeurotechEU

November 2020 marks the official start of The European University NeurotechEU.

NeurotechEU will educate students across all levels (bachelor’s, master’s, doctoral as well as life-long learners) and train the next-generation multidisciplinary scientists, scholars and graduates, provide them direct access to cutting-edge infrastructure for fundamental, translational and applied research to help Europe address this unmet challenge.

Heterogeneity of perisynaptic astroglia, its changes and functional consequences

Synapses in the brain are approached by perisynaptic astrocyte processes, which are important for the clearance of the neurotransmitter glutamate, for instance. But the coverage of synapses by theses astrocytic processes varies considerably from synapse to synapse. In a first recent study, we could demonstrate that stronger synapses are covered less, relative to their size, and uptake of glutamate is less efficient at these synapses, which increases the probability of synaptic crosstalk. In a second recent study, we could reveal that induction of synaptic long-term potentiation, a cellular mechanism underlying learning, but not depression can trigger the withdrawal of astrocytic processes from synapses and increase synaptic crosstalk. Together, both studies show that the geometrical arrangement of synapses and persisynaptic astrocyte processes is dynamically regulated and defines the spatial precision of synaptic transmission.

Herde K, Bohmbach K, Domingos C, Vana N, Komorowska-Müller JA, Passlick S,  Schwarz I, Jackson CJ, Dietrich D, Schwarz MK, Henneberger C (2020) Local efficacy of glutamate uptake decreases with synapse size. Cell Rep. 32(12):108182 (link)

Henneberger C, Bard L, Panatier A, Reynolds J, Kopach O, Medvedev NI, Minge D, Herde MK, Anders S, Kraev I, Heller JP, Rama S, Zheng K, Jensen TP, Sanchez-Romero I, Jackson C, Janovjak H, Ottersen OP, Nagelhus EA, Oliet SHR, Stewart MG, Nägerl UV, Rusakov DA (2020) LTP induction boosts glutamate spillover by driving withdrawal of perisynaptic astroglia. Neuron (in press) (link)

Astroglial Resting Calcium Controls the Scale of Calcium Signals

Astroglia can encode their activity by the generation of Ca2+ signals, which then trigger or modify various functions of the cell. The signalling pathways that generate Ca2+ signals have been explored in detail. However, what controls their amplitude and waveform remains poorly understood. Using an array of optical methods in vitro and in vivo, we, i.e., Claire King, Kirsten Bohmbach and further colleagues have explored how the resting Ca2+ concentration controls these signals. We consistently find that peak and amplitude of Ca2+ signals display an opposite dependence on the resting Ca2+: a previously unrecognized basic rule underlying Ca2+ signalling in astroglial. The study has been published in Cell Report.

King CM, Bohmbach K, Minge D, Delekate A, Zheng K, Reynolds J, Rakers C, Zeug A, Petzold GC, Rusakov DA, Henneberger C (2020) Local Resting Ca2+ Controls the Scale of Astroglial Ca2+ Signals. Cell Rep. 30(10):3466-3477 (link, open access)

For a more in-depth discussion of astrocytic Ca2+ signalling please see our recent review.

Semyanov A, Henneberger C, Agarwal A (2020) Making sense of astrocytic calcium signals — from acquisition to interpretation. Nat. Rev. Neurosci. 21(10):551–564. (link)