. .

Search

Your contact person:



Dr. Johannes Seelig
Neural Circuits
+49 (0)228 9656-190

Neural Circuits

In navigating the world we combine information about external sensory cues with information from our motor system. We base subsequent motor actions on the integration of these two different streams of sensory and motor information. Fruit flies solve this computational problem with a small brain of around 100,000 neurons. This comparatively small size makes the fly attractive for analyzing neural circuits that span the entire brain, such as those underlying sensorimotor integration.  The similarities at the molecular level (for example an estimated 60% of genes are conserved between humans and flies) as well as structural and functional similarities at the level of neural circuits (as established for example for the visual or olfactory system) suggest that insights gained in the fly brain might also contribute to our understanding of sensorimotor integration in larger brains.

In Vivek Jayaraman’s lab at Janelia we have developed preparations that allow us to observe neural activity in the fly’s brain while it walks or flies in a virtual reality environment. Two-photon excitation together with the genetic tools available in the fly, then allow us to image and stimulate identified populations of neurons underlying sensorimotor integration throughout the brain. In recent work in Vivek’s lab we found maplike populations of neurons in the central brain that feed information about visual features into a larger circuit that (at least in part) underlies the fly’s navigational behavior. The function and structure of this circuit is intriguingly similar to basic computational models that have been proposed for the description of much larger navigational systems in the mammalian brain. The fly brain seems to offer a compact and comprehensively accessible implementation of a more broadly relevant network motif. 

In current work our lab focuses on the impact of neuromodulators on circuits underlying sensorimotor integration. Similar to the mammalian brain the fly brain is broadly innervated by neuromodulatory neurons. Taking advantage of the lower numerical complexity of the fly brain should allow us to get a quantitative understanding of the impact of neuromodulators on complete neural circuits underlying sensorimotor integration.