Fig. 7.

A, Data for the first button press session for subject 2 (overall session 2; session 1 was the covert count condition). Here the circles were targets, and the pictures of everyday objects were task-irrelevant novels. Activation was evoked in the MFG bilaterally (right dominant) for the target circles only.B, Data for the second button press session (overall session 3) for subject 2 in which the response rules were switched. Now the circles were task-irrelevant (novels) and the pictures of everyday objects were the task-relevant targets. Bilateral activation of the MFG was evoked by the picture targets but not by the circle novels. Thus, MFG activation was evoked by whichever stimulus category was designated as target. C, Results for subject 3 depicted for a choice response task in which one button was pressed for both novels and standards and a second button was pressed for targets. Targets evoked strong activation of the MFG, just as they had in this subject's initial session when only a single button press was required for targets. Although now requiring the same button press response as the standards, the novels evoked no such activation.