Figure 3 .

Youthful neural differentiation supports better memory in older adults. (A) Older adults with greater neural differentiation during encoding of distinct categories of visual information show better associative memory for that information after a delay. That is, older adults whose brains function more like those of young adults to differentiate all face–word pairs from all scene–word pairs when learning the information remember more individual image–word pairs when later tested on that information. Memory performance is expressed as d′ (recognition discriminability; see Materials and Methods). (B) The neural differentiation effect shown in (A) is illustrated using RS matrices from two individuals labeled in (A): a 70-year-old superager (indicated by a red circle/arrow in (A); top matrix here) whose RS for within-category trial pairs was 0.49, whose RS for between-category trial pairs was −0.10, neural differentiation was thus 0.59, and whose d′ was 1.58; and a 64-year-old typical older adult (indicated by a blue circle/arrow in (A); bottom matrix here) whose RS for within-category trial pairs was 0.10, whose RS for between-category trial pairs was 0.05, neural differentiation was thus 0.05, and whose d′ was 0.26. These matrices show, at the individual level, the effect shown at the group level in Figure 2C: When superagers learn information, their regional brain activity shows greater RS within distinct categories of information than when typical older adults learn information, and they remember that information better later.