Detection of first and second order motion

A model of motion detection is presented. The model contains three stages. The first stage is unoriented and is selective for contrast polarities. The next two stages work in parallel. A phase insensitive stage pools across different contrast polarities through a spatiotemporal filter and thus can detect first and second order motion. A phase sensitive stage keeps contrast polarities separate, each of which is filtered through a spatiotemporal filter, and thus only first order motion can be detected. Differential phase sensitivity can therefore account for the detection of first and second order motion. Phase insensitive detectors correspond to cortical complex cells, and phase sensitive detectors to simple cells

Activity in area V3A predicts positions of moving objects

No description supplie

Detection of First and Second Order Motion

A model of motion detection is presented. The model contains three stages. The first stage is unoriented and is selective for contrast polarities. The next two stages work in parallel. A phase insensitive stage pools across different contrast polarities through a spatiotemporal filter and thus can detect first and second order motion. A phase sensitive stage keeps contrast polarities separate, each of which is filtered through a spatiotemporal filter, and thus only first order motion can be detected. Differential phase sensitivity can therefore account for the detection of first and second order motion. Phase insensitive detectors correspond to cortical complex cells, and phase sensitive detectors to simple cells. 1 INTRODUCTION In our environment objects are constantly in motion, and the visual system faces the task of identifying the motion of objects. This task can be subdivided into two components: motion detection and motion integration. In this study we will look at motion dete..

Increased sensitivity to speed changes during adaptation to first-order, but not to second-order motion

Observers adapted to drifting patterns varying either in luminance (first-order pattern), or in contrast (second-order pattern). Sensitivity to increases or decreases in the speed of the first-order pattern increased sharply as adaptation time increased, but sensitivity to speed changes of the second-order pattern remained unchanged throughout the adaptation time. Adaptation of first-order motion mechanisms seems thus to mediate increased sensitivity to variations in speed around the adapting speed. No evidence was found for such effects of adaptation to second-order motion. The observed differences in the effects of adaptation accord well with reports of fundamental differences between after-effects to drifting first- and second-order patterns and are in harmony with models of motion perception emphasizing different mechanisms for the detection of first- and second-order motion