Spatial localization and the refinement of orienting behavior: What can be learned from the barn owl?

The barn owl is a nocturnal predator that relies on audition for hunting. In addition to being able to localize sound sources with high accuracy, it can adjust its orienting behavior in the presence of changes in sensorimotor conditions (e.g. through growth). We review our work modeling the principal neural structures responsible for the orienting behavior of the barn owl. To expose these models to realistic sensorimotor and environmental conditions, we coupled the simulation of the neural structures with a robot that emulates the owl's head. This system was composed of a robotic head with two lateral microphones and a camera, and was presented with auditory and visual stimulation. This work has allowed a deeper understanding of how the barn owl reliably localizes a sound source, by elucidating some of the mechanisms underlying the rejection of noise. In addition, it has led to the formulation of a learning scheme accounting for a wide range of biological observations on how the barn owl calibrates orienting behavior. The resulting system was able to orient accurately toward visual and auditory targets, while maintaining accurate performance even in the presence of manipulations of the sensory or motor conditions. This work provides a direct example of how an interdisciplinary approach, based on the coupling of computer simulation of brain structures with robotic systems, can lead to the understanding of basic biological problems while producing robust and flexible control of systems that operate in the real world.