DocumentCode :
1914988
Title :
Cortical dynamics of motion integration and segmentation
Author :
Mingolla, Ennio
Author_Institution :
Dept. of Cognitive & Neural Syst., Boston Univ., MA, USA
Volume :
1
fYear :
2003
fDate :
20-24 July 2003
Firstpage :
16
Abstract :
A neural model is developed of how motion integration and segmentation processes compute global motion percepts. Figure-ground properties, such as occlusion, influence which motion signals determine the percept. For visible apertures, a line´s extrinsic terminators do not specify true line motion. For invisible apertures, a line´s intrinsic terminators create veridical feature tracking signals, which are amplified before they propagate across space and are integrated with ambiguous motion signals within line interiors. This integration process is the result of several processing stages. Directional transient cells respond to image transients and input to a directional short-range filter that selectively boost feature tracking signals. Competitive interactions further boost feature-tracking signals and create speed-selective receptive fields. A long-range filter gives rise to true directional cells by pooling signals over multiple orientations and opposite contrast polarities. A distributed population code of speed tuning realizes a size-speed correlation, whereby activations of multiple spatially short-range filters of different sizes are transformed into speed-tuned cell responses. These mechanisms use transient cell responses, output thresholds that covary with filter size, and competition. The model reproduces empirically derived speed discrimination curves and simulates data showing how visual speed perception and discrimination are affected by stimulus contrast.
Keywords :
brightness; image motion analysis; neural nets; neurophysiology; physiological models; velocity; visual perception; cortical dynamics; figure-ground properties; global motion percepts; long-range filters; motion integration; motion segmentation; neural model; occlusion; short-range filters; speed discrimination curves; stimulus contrast; visual speed perception; Apertures; Detectors; Filters; Gratings; Layout; Motion detection; Motion measurement; Signal processing; Velocity measurement; Visual system;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Neural Networks, 2003. Proceedings of the International Joint Conference on
ISSN :
1098-7576
Print_ISBN :
0-7803-7898-9
Type :
conf
DOI :
10.1109/IJCNN.2003.1223260
Filename :
1223260
Link To Document :
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