Quantal processing of visual information in the brain.

In order to test if vision is a continuous processing system that analyses information immediately after it arrives at the retina or a discontinuous system that accumulates information and periodically analyses a data quantum, the time required by 38 healthy adults to solve simple visual tasks was accurately quantified. The main finding of the present study was that the processing time for visual tasks is always a multiple of a basic unit whose duration was 30-40 ms. Present data support the hypothesis that visual information is processed in the brain with a discontinuous flow of discrete-time quanta. Data suggest two processing ways for the visual system, one that with a high time-resolution (30-40 ms) operates under high-illumination conditions, and the other that with a low time-resolution (100-120 ms) is put into operation in low-illumination conditions.