Converting an allocentric goal into an egocentric steering signal.

Neuronal signals that are relevant for spatial navigation have been described in many species. However, a circuit-level understanding of how such signals interact to guide navigational behaviour is lacking. Here we characterize a neuronal circuit in the Drosophila central complex that compares internally generated estimates of the heading and goal angles of the fly-both of which are encoded in world-centred (allocentric) coordinates-to generate a body-centred (egocentric) steering signal.

Comparative Development of the Ant Chemosensory System.

The insect antennal lobe (AL) contains the first synapses of the olfactory system, where olfactory sensory neurons (OSNs) contact second-order projection neurons (PNs). In Drosophila melanogaster, OSNs expressing specific receptor genes send stereotyped projections to one or two of about 50 morphologically defined glomeruli [1-3]. The mechanisms for this precise matching between OSNs and PNs have been studied extensively in D.

A neural heading estimate is compared with an internal goal to guide oriented navigation.

Goal-directed navigation is thought to rely on the activity of head-direction cells, but how this activity guides moment-to-moment actions remains poorly understood. Here we characterize how heading neurons in the Drosophila central complex guide moment-to-moment navigational behavior. We establish an innate, heading-neuron-dependent, tethered navigational behavior where walking flies maintain a straight trajectory along a specific angular bearing for hundreds of body lengths.