Figure 4.

Positive and Negative Modulation to Difficulty Decrease Differentially across the Lifespan. Simple slopes analysis was used to decompose the significant age x positive modulation and age x negative modulation interactions. A) Aging of positive modulation to difficulty declines linearly with age, and simple slope remains significantly different from zero until around age 99 (dotted line) at which point there would be a failure to modulate (i.e., no difference in BOLD response across difficulty conditions). B) Negative modulation declines with age (decreased deactivation to difficulty) and failure to modulate begins around age 71 (dotted line).