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C2 - Minimal models for oscillations, assembly formation, and transitions in PFC and HC-networks

Principal investigator(s):

Institut für Physiologie & Pathophysiologie
Universität Heidelberg
Im Neuenheimer Feld 326
69120 Heidelberg


Projects within the BCCN:

Project C2 aimed at developing a minimal model for neuronal network oscillations. We wanted to compare different basic architectures, especially the different role of excitatory and inhibitory neurons. Ultimately, the minimal conditions for networks with transitions between different dynamic states should be uncovered.
A. Stevens and coworkers developed a model based on synchronously active inhibitory interneurons resulting in a widespread rhythmic inhibition of all excitatory cells. A first result was that a fast decay time course of inhibition stabilizes network oscillations. This prediction is experimentally testable, since several drugs are known to affect the time course of inhibitory postsynaptic potentials (Viereckel et al., 2013). As a second result, adding a further, different interneuron could destabilize the resulting patterns. The crucial property of the additional interneuron was that it caused inhibitory potentials with a faster decay rate than the other interneurons in the network. Again, this finding may have a direct biological correlate, since many neuronal networks contain different types on interneurons with different postsynaptic kinetic properties.
During the later phase of the project, we concentrated on experimental approaches allowing to manipulate activity of interneurons or principal cells in active networks. An important prerequisite for recording from large neuronal populations was the implementation and validation of data analysis tools for optical recording methods in brain slices (Reichinnek et al., 2012). For this, we implemented optogenetic techniques in the laboratory and optimized an electrophysiological apparatus for optical stimulation of small groups of neurons while recording activity from multiple locations (so-called multi-electrode array, MEA).
After the move of Prof. Angela Stevens to Münster University, the experimental part of the project was strengthened. This did, however, not include significant deviations from the work program.
Most of the experimental results have been published, while the minimal network model and the optogenetic manipulations are still in manuscript state. All remaining data and findings will probably be published within the near future.

Participating groups:

Key publications:

Nguyen Chi V, Müller C, Wolfenstetter T, Yanovsky Y, Draguhn A, Tort AB, Brankačk J (2016) Hippocampal Respiration-Driven Rhythm Distinct from Theta Oscillations in Awake Mice J Neurosci 36:162-177 .
Thome C, Kelly T, Yanez A, Schultz C, Engelhardt M, Cambridge SB, Both M, Draguhn A, Beck H, Egorov AV (2014) Axon-Carrying Dendrites Convey Privileged Synaptic Input in Hippocampal Neurons Neuron 83:1418–1430 .
Yanovsky Y, Ciatipis M, Draguhn A, Tort ABL, Brankack J (2014) Slow Oscillations in the Mouse Hippocampus Entrained by Nasal Respiration J. Neuroscience 34:5949 –5964 .
Reichinnek S, von Kameke A, Hagenston AM, Freitag E, Roth FC, Bading H, Hasan MT, Draguhn A, Both M (2012) Reliable optical detection of coherent neuronal activity in fast oscillating networks in vitro Neuroimage 60:139-152 .
Bähner F, Weiss EK, Birke G, Maier N, Schmitz D, Rudolph U, Frotscher M, Traub RD, Both M, Draguhn A (2011) Cellular correlate of assembly formation in oscillating hippocampal networks in vitro Proc Natl Acad Sci U S A 108:E607-616 .