Figure 1.

Illustration of the experimental design and paradigm. A, Trials were presented using a mixed event-related and block design with % validity (90% or 60%) being manipulated across different blocks. The % validity was indicated to the subjects by instruction as well as by the color of the cue (blue or orange). B, In the example shown here, the subject was asked to discriminate the orientation of the green grating while maintaining fixation at the center of the display (i.e., the dot in the diamond).