Iterative cooperation between parallel pathways for object and background motion

In a typical visual scene, one or more objects move relative to a larger background, which can itself be in motion as a result of the observer's eyes moving with respect to the outside world. Here we show that accurate estimation of the background motion from an image velocity field can be accomplished through an iterative cooperationbetweentwomodules:onethatspecializesin calculating a weighted average velocity and another one calculatingavelocitycontrastmap.Webuildonouranalysis to provide a model for the tectum-pretectum loop in the nonmammalian midbrain. Our model accounts for some of the known properties of the tectal neurons (sensitivity to relative motion) and pretectal neurons (sensitivity to whole-field motion). It also agrees with our knowledge of the pretectotectal projection (divergentandinhibitory),andwiththeresultsoflesionstudies in which the pretectal input to the tectum was removed, leadingtohyperactivityofthetectalneuronsandtheanimal. Our model also makes a testable...

• Type: Journal
• Year: 2006
• Where: BC
• Authors: Alireza S. Mahani, Ralf Wessel
• Keywords: Background Motion, BC 2006, Typical Visual Scene, Weighted Average Velocity