Timing and competition in networks representing ambiguous figures.

The duration of perception for eye rivalry and the Necker cube was obtained during continuous presentation of the stimuli. The frequency histograms support the idea of continuous competition between the neural representations of both percepts. They also suggest that when a percept is installed there is a relative refractoriness for changing the percept that is modeled by a sigmoid equation. This refractoriness lasts a few seconds. The duration of the perceptions was modified by the instruction to the subjects. Results are discussed in terms of a simple competition model, a temporal segmentation hypothesis, and the possible top-down influences. These are considered useful mechanisms for selecting relevant information in a serial processor and for maintaining perception, cognitive evaluation, and action of a given context in the same time epoch.