Figure 1. Schematic demonstration of the visual stimuli used in the present study.

A: stationary flash stimulus, duration of the presentation of the bright (ON) and the dark (OFF) monitor lasted for 1s each. B: moving ON stimulus. A light edge moved across the dark monitor until it was fully bright in the four cardinal directions. C: moving OFF stimulus. A dark edge moved across the bright monitor until it was fully dark in the four cardinal directions (for further description see methods).