Figure 1.

WM Task. During fMRI scanning, subjects performed a Sternberg task consisting of 72 trials per condition (Load 4 and Load 2) in each of 8 runs. Subjects viewed either 2 or 4 sequentially presented images of outdoor scenes (encoding phase), maintained the scenes across a 4- to 8-s variable-length delay period (maintenance phase), and determined whether a probe scene matched one of the previous images seen during that trial or was a nonmatch (test phase). Each trial ended with a variable-length fixation/ITI.