Figure 1. Natural scene movies with modified surrounds.

Timeline for presentation of natural scenes movies. 200 ms after the start of the trial a red fixation point appeared in the middle of a black background. The monkey was required to press and hold a lever between 200 and 900 ms. The natural scenes movie (FF, AM or TR) began at 1000 ms. At 3800 ms the fixation point changed color from red to green. The monkey was then required to release the lever between 4000 and 4300 ms.