[The Nervous Control of Gaze Orientation]

This short paper presents and discusses some new findings and hypotheses in the field of saccadic gaze control. After a general introduction to the function of eye movements, the physiology of the deep layers of the superior colliculus are reviewed. Recent experimental data suggest the existence of an internal feedback of gaze velocity which updates this retinotopically organised map, in real time, during the execution of the movement. This mechanism also permits a precise feedback control of such a fast movement, for which a classical external feedback is not possible, due to time delay. Another virtue of this spatially distributed feedback is that it elegantly solves the spatio-temporal transformation problem inherent to such a sensorimotor interface. Indeed, the visual input is topographically coded within its early processing by the brain (place code), whereas the motor output is sequentially coded (time code). This hypothesis has been computer-modelled and simulated. Further experimental data are however needed to confirm it.