Combining molecular biology with live cell imaging and electrophysiological techniques, we will study the trigeminal system of rat in vitro and in vivo. In primary cell cultures of trigeminal ganglion neurons we will identify and functionally characterize molecular players participating in odor and astringency perception using calcium imaging and patch clamp recordings. The results from this part of the project will shed light on the molecular mechanisms of peripheral trigeminal perception. Next we will transfer our results obtained from in vitro studies to the in vivo situation in the intact trigeminal ganglion of rat. We already established a preparatory approach that allows extracellular electrical recordings of neuronal activity and an high resolution of optical signals arising from the intact rat trigeminal ganglion by imaging technology. Using voltage-sensitive dyes we will analyze whether stimulus specific spatiotemporal activation patterns exist at the level of the trigeminal ganglia. These results may not only be important for a better understanding of trigeminal chemoperception but should in general help to expand our knowledge about information processing in peripheral nervous systems.