Linking dynamical perceptual decisions at different levels of description in motion pattern formation: psychophysics.

The relationship between local-level motion detection and higher level pattern-forming mechanisms was investigated with the motion quartet, a bistable stimulus for which either horizontal or vertical motion patterns are perceived. Local-level perturbations in luminance contrast affected the stability of the perceived patterns and, thereby, the size of the pattern-level hysteresis obtained by gradually changing the motion quartet's aspect ratio. Briefly eliminating luminance contrast (so nonmotion was perceived during the perturbation) eliminated pattern-level hysteresis, and briefly increasing luminance contrast (so motion was perceived during the perturbation) increased pattern-level hysteresis. Partially reducing luminance contrast resulted in bistability during the perturbation; pattern-level hysteresis was maintained when motion was perceived, and eliminated when nonmotion was perceived. The results were attributed to local motion/nonmotion perceptual decisions in area V1 affecting the magnitude of the activation feeding forward to motion detectors in area MT, where the stability of pattern-level perceptual decisions is determined by activation-dependent, future-shaping interactions that inhibit soon-to-be-stimulated detectors responsive to competing motion directions.