We employ various techniques and tools that allow visualization of cell type specific synapses in vivo at the light microscopic and ultrastructural level. Furthermore, we combine structural circuit analysis with functional calcium imaging, optogenetics and behavior to get in depth insight into network connectivity and function on all levels.

Genetics

Drosophila is a geneticist's heaven. The community has generated many tools to manipulate genes and circuits with high temporal and spatial precision.  Moreover, about 75% of all genes linked to human disease are conserved in flies, and genetic redundancy in Drosophila is very low compared to higher organisms. This allows us to uncover a gene's basic function(s) in vivo using molecular genetic approaches. In the age of CRISPR/Cas-mediated genome editing, genetic analysis has gotten even more efficient and powerful. Our lab is employing all available genetic strategies including binary expression systems (Gal4/UAS, LexA/LexAop, Q-System), RNAi, CRISPR/Cas9 to functionally and molecularly dissect the somatosensory network in an effort to understand the basis of its form and function.

In vivo imaging

Sensory neurons are fully accessible to confocal microscopy due to their localization close to the larval bodywall. We perform high resolution  imaging in fixed and live larvae to investigate dendrite morphology and dynamics, synaptic connectivity and cellular/molecular interactions. We also analyze dendrite, cytoskeletal and organelle dynamics using time-lapse imaging in vivo. Lastly, we perform physiological calcium imaging with genetically encoded sensors (GCamP6) to probe neuronal responses to optogenetic or mechanical stimulation.

Connectomics and electron microscopy

Recent efforts in electron microscopy based reconstruction of the larval connectome and genetic tool development have opened novel avenues to understand network connectivity and function. We are involved  in reconstructing the larval somatosensory network and use immuno-electron microscopy approaches to label cell type specific synapses in the larval brain at the ultrastructural level.

Optogenetics and functional imaging

We are using optically activatable channels and sensors to probe circuit function and behavior. We combine optogenetic activation or silencing of neurons with functional calcium imaging and behavioral readouts, which allow us to get insight into network activity and function, respectively.
We are also involved in developing and testing novel optogenetic actuators, e.g. to silence neuronal function or trigger G protein coupled receptor signaling.

Behavior

Behavior is arguably the most important readout for gene or circuit function. Therefore, we incorporate behavioral analysis to understand how morphological or functional changes in our circuits are resulting in behavioral abnormalities. In our lab we use high resolution larval locomotion tracking, nociceptive and mechanosensory behavioral assays. We also employ optogenetic activation and inhibition to dissect molecular and circuit functions at the behavioral level.