Fig. (1) Coloured filters are the most frequently used method for dichoptic visual stimulation. During the experiment, the subject views the stimuli through a pair of coloured red-green goggles (A). The light reaches the viewing screen either through a coloured filter standing in front of the projector (B and C) or red/green stimuli are directly projected onto the screen (D) (Method first described by Sireteanu and co-workers (1998) [9]. Photographs made by Natalie Tonhausen).