What always fascinated me about working in the fields of electrophysiology and neurobiology was the opportunity to gain insight into neural processes and molecular mechanisms by observing nerve cells in a direct, immediate way.

As a classical subject for in vivo experiments, insects like Calliphora provide not only a comparatively simple, yet powerful model for the investigation of neural circuitry but also the possibility to work with a wide range of different techniques.

In my current project, I use direct imaging of neuronal activity of fly tangential cells via multifocal two-photon microscopy to investigate how the highly ordered direction tuning of these motion-sensitive visual neurons relies on dendritic topology.

In comparison to conventional fluorescence microscopy, the use of infrared light with two-photon illumination avoids excitation of the fly's photoreceptors and reduces tissue damage due to photobleaching. Injecting the cells with calcium-sensitive fluorescent dyes and scanning at high temporal rate makes it possible to directly observe the dynamic changes in calcium concentration during activity of input synapses, while the multifocal laser arrangement allows to monitor and compare several synaptic sites at the same time.