Le séminaire iPAC du 13 octobre 2011 aura lieu dans l'Amphi du LORIA (Nancy) à 13h30. This talk will be given in english.

Orateur: Heiko Neumann , Institute of Neural Information Processing, Ulm University, Allemagne

Titre : Neural mechanisms of motion perception – from experiments to neural models.

Transparents : au format PDF.

Résumé : One of the basic operations in visual processing is the detection of temporally varying structure and their grouping. Higher order processing deals with the disambiguation and segmentation of motion in complex scenes with objects that may be partially occluded. In primate visual cortex early and mid-level computation along the dorsal stream contributes to the generation of coherent motion representations from ambiguous local measurements. These processes help, e.g., to overcome the aperture problem, to segregate figures from background based on motion, and to generate perceptions of transparent motion.

In the talk a neural model is presented which suggests key mechanisms of cortical visual motion processing such as, e.g., (non-linear) filtering for feedforward feature integration, modulating feedback, and lateral (divisive) inhibition. It will be demonstrated that these mechanisms explain a wealth of data in motion perception and in the steering of perceptual behavior. In particular, we argue that competitive center-surround processes operating on the velocity representation and feedback mechanisms define the key to account for segregating transparent motions. In addition, we show how smooth pursuit eye movements are corrected in a time-course that parallels the motion disambiguation process.

Work supported by European Union (SEARISE), BMBF and DFG