The fast communication between and within neuronal networks is based on the excitability of individual neurons and their connectivity to other neurons. In this respect, neurons can be seen as computational devices that integrate information from multiple synaptic contacts and transform this information into an output function. Within synaptic contacts, the number of signaling molecules, like presynaptic calcium channels and postsynaptic receptors, is in the order of a few tens to hundred molecules. Considering the stochastic nature of ion channel gating and the ability of integral proteins to change rapidly their position in the cell membrane, we address the question to which extent such “molecular noise” modulates the input-output relation of a particular neuron and will change neuronal network activity.
Dynamics of molecules in the cell membrane of neurons is important within the nanometer range, a spatial scale that is most relevant within synapses. Here, we focus on voltage-gated calcium channels, synaptic adhesion molecules and postsynaptic ionotropic receptors. With the use of super resolution microscopy, we are able to look into synapses (200-500 nm large) and observe the motion of individual ion channels. Combining this approach with fluorescence-based functional readouts and electrophysiology, we explore the function of molecular dynamics in neuronal communication and memory formation. Interventions on the dynamics of single molecules revealed that local mobility of AMPA receptors and CaV2.1 channel has direct impact on the short-term plasticity of central synapses (Heine et al. 2008, Schneider et al. 2015, Heck et al. 2019).
These are our current research topics:
Calcium channel dynamics within the neuronal membrane
Mobility of adhesion molecules within synapses
Dynamic interactions of calcium channel subunits
Transfer, integration and storage of information in neuronal networks