Seminar on Motion Processing

by Miriam Spering (University Giessen)

 

To receive more information about the seminar or if you wish to meet with Miriam, please contact

Philippe Lefèvre: http://perso.uclouvain.be/philippe.lefevre

 

 

 

 

Monday July 2nd, 2007

Location: Salle de séminaire Harvey +1, UCL Brussels

Time:

   12:30 ”Different mechanisms of motion processing for perception and pursuit eye movements”

 

   Abstract: The analysis of visual motion serves many different functions ranging from object motion perception to the control of self-motion. The perception of visual motion and the oculomotor tracking of a moving object are known to be closely related and are assumed to be controlled by shared brain areas. I will report results from experiments in which we compared perceived velocity and the velocity of smooth pursuit eye movements in human observers in a paradigm requiring the segmentation of target object motion from context motion. In each trial, a pursuit target and a visual context were independently perturbed simultaneously to briefly increase or decrease in speed. Observers had to accurately track the target and estimate target speed during the perturbation interval. Results show that the same motion signals are processed in fundamentally different ways for perception and smooth pursuit eye movements. For the computation of perceived velocity, motion of the context was subtracted from target motion (motion contrast), whereas pursuit velocity was determined by the motion average (motion assimilation). I will conclude that the human motion system uses these computations to optimally accomplish different functions: image segmentation for object motion perception and velocity estimation for the control of smooth pursuit eye movements.

 


 




last update: June 28th, 2007
Author:  Philippe LEFEVRE