We have investigated how sensory signals cross the first synapse in the cerebellar cortex.
We combined patch-clamp recordings of synaptic currents with quantal statistical analysis
and models of short term synaptic plasticity
to establish that cerebellar mossy fibre terminals
have an unusually large resource of vesicles (300 per site)
and that vesicles can be docked and primed much faster (~12 ms)
than previously thought for central synapses
(Saviane and Silver 2006
By developing a quantitative glutamate uncaging method
that combines photolysis with 3D reaction-diffusion modelling,
we characterized AMPA receptor desensitization within the synapse
(Digregorio et al. 2007
This showed that synaptic AMPARs are more resistant to desensitization
than previously thought, allowing them to convert glutamate
arising from spillover into current without desensitizing.
These pre- and post-synaptic properties allow the cerebellar mossy fibre-granule cell synapse
to signal over an unusually wide bandwidth.
We have recently extended this work to the molecular level,
in collaboration with Stefan Hallermann, Eckart Gundelfinger and Jens Eilers,
by establishing that the synaptic protein Bassoon underlies this fast reloading of vesicles
(Hallermann et al. 2010
We have also investigated how vestibular information
is encoded by mossy fibre synapses, in collaboration with Troy Margrie,
by performing in vivo
patch-clamp recordings from granule cells
(Arenz et al. 2008
This demonstrated that angular velocity is linearly related to synaptic charge.