The Synaptic Nanophysiology group aims to decipher the mechanisms of synaptic transmission at the hair cell ribbon synapse and the giant calyceal synapses of the central auditory pathway, foremost the endbulb of Held synapse in the cochlear nucleus. We are interested in the mechanisms that enable the impressive temporal precision and long-lasting reliability of synaptic transmission in the early auditory pathway. We approach these questions by a systematic analysis of the molecular nanoanatomy and nanophysiology of hair cell ribbon synapses and endbulb of Held synapses in normal and molecularly manipulated mice.
We perform pre- and/or postsynaptic patch-clamp measurements to stimulate and record synaptic transmission at high resolution and to manipulate the synapse. Whole-cell and cell-attached measurements of membrane capacitance are used to report exocytic and endocytic membrane turnover in the presynapse. The apparent and intrinsic Ca2+ dependence of exocytosis is studied by manipulating the Ca2+ current and uncaging of caged Ca2+, respectively. Confocal and STED microscopy are applied for studies of molecular anatomy and physiology of these synapses.
The focus of functional imaging is on Ca2+ signaling and vesicle turnover at individual active zones. Imaging also builds on collaboration with the Dept. of Nanobiophotonics of Stefan Hell. We use the acquired morphological and functional data as input into our biophysical modeling that we perform in collaboration with Fred Wolf, Theoretical Neurophysics Group, MPI for Dynamics and Self-Organization and which in return helps us to further test our hypotheses and design new experiments. Funding comes from the Max-Planck-Society, the University Medical Center Göttingen and the DFG through the Collaborative Research Center 889 and the Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain.