Figure 1.

Behavioral task and performance. A, Behavioral task with the three randomly interleaved trial types. Blue dashed circles represent the focus of covert attention. Pink dashed circles indicate orientation change(s). Pink arrows indicate saccadic eye movements. Blue dot represents gaze position. B, Average behavioral performance of each subject under placebo sessions only. The colors indicate the proportion of each trial outcome in a behavioral session. Fixation break represents errors where the subject would respond before a Go signal was given. Sac. to distractor represents errors where the subject would respond to a distracting stimulus. No response represents trials where the subject would not provide a response. C, D, Line plots representing the change in overall hit rate relative to matched placebo sessions in the attention task following various doses of MPH. Hit rate is considered a proportion (Hit/Hit+Errors). Differences in proportion (hit rate) across treatment conditions are computed with χ² tests. Asterisks represent statistically significant changes in hit rate relative to placebo sessions (χ² test, p < 0.05). E, F, Same format as C, D but representing the proportion of specific error types across treatment conditions. Up means more errors. Refer to Materials and Methods for definitions. Error bars represent the SE of the sample proportion estimate.