Figure 3. Statistical parametric maps (SPMs) of the group analysis (4 young and 4 elderly healthy male volunteers, 3 functional magnetic resonance imaging [fMRI] exams per subject) during “n-back” spatial working memory task versus control. In the control condition (“O-back”), subjects had to respond when a square appeared in a given position on the computer screen; in the “1-back” condition, when it appeared in the same place as 1 screen before; in the “2-back” condition when it appeared in the same place as 2 screens before. In both the 1 -back and the 2-back tasks, accuracy score was similar in elderly and young subjects. Reaction time was similar in the two groups during the 1 -back task, but significantly longer in the elderly group during the 2-back task. Significant activity (t-score>4) is displayed upon anatomical axial T1 images after being transformed to standardized Talairach space.
