Compensatory neural activity distinguishes different patterns of normal cognitive aging

Abstract

Most cognitive neuroscientific research exploring the nature of age-associated compensatory mechanisms has compared old adults (high vs. average performers) to young adults (not split by performance), leaving ambiguous whether findings are truly age-related or reflect differences between high and average performers throughout the lifespan. Here, we examined differences in neural activity (as measured by ERPs) that were generated by high vs. average performing old, middle-age, and young adults while processing novel and target events to investigate the following three questions: 1) Are differences between cognitively high and average performing subjects in the allocation of processing resources (as indexed by P3 amplitude) specific to old subjects, or found throughout the adult lifespan? 2) Are differences between cognitively high and average performing subjects in speed of processing (as indexed by target P3 latency) of similar magnitude throughout the adult lifespan? 3) Where along the information processing stream does the compensatory neural activity attributed to cognitively high performing old subjects begin to take place? Our results suggest that high performing old adults successfully manage the task by a compensatory neural mechanism associated with the modulation of controlled processing and the allocation of more resources, whereas high performing younger subjects execute the task more efficiently with fewer resources. Differences between cognitively high and average performers in processing speed increase with age. Middle-age seems to be a critical stage in which substantial differences in neural activity between high and average performers emerge. These findings provide strong evidence for different patterns of agerelated changes in the processing of salient environmental stimuli, with cognitive status serving as a key mediating variable.

Preserved executive function in high‐performing elderly is driven by large‐scale recruitment of prefrontal cortical mechanisms

“…On the other hand, the HP-elderly group showed a robust P3. A number of recent studies that also focused on performance differences within the elderly population have confirmed increased P3 amplitude in HP-elderly [e.g., Daffner et al, 2005Daffner et al, , 2006Riis et al, 2008].…”

“…Normal aging has been associated with progressive deterioration in this switching ability [e.g., Cepeda et al, 2001;Paul et al, 2005;Wecker et al, 2005;West and Travers, 2008]. However, in the elderly, there is remarkable variability in the ability to effectively perform executive control tasks, with some showing pronounced deterioration with advancing years and others continuing to perform as well as their younger counterparts [see e.g., Riis et al, 2008]. The neural mechanisms that allow some elderly subjects to preserve high levels of executive control are a matter of acute interest, since the design of effective intervention strategies will ultimately depend on fundamental knowledge regarding the mechanisms that allow for successful aging.…”

Effects of aging on habituation to novelty: An ERP study

“…Friedman et al, 1993Friedman et al, , 1998Friedman and Simpson, 1994) whilst others demonstrate stability or even improvement (e.g. Daffner et al, 2006;Riis et al, 2008). Nonetheless, there is consensus that such change reflects age-related modification to frontal lobe function (Daffner et al, 2006;Friedman et al, 1998;Friedman and Simpson, 1994;Friedman et al, 1993;Riis et al, 2008).…”

“…Daffner et al, 2006;Riis et al, 2008). Nonetheless, there is consensus that such change reflects age-related modification to frontal lobe function (Daffner et al, 2006;Friedman et al, 1998;Friedman and Simpson, 1994;Friedman et al, 1993;Riis et al, 2008). However, there is little empirical support for a direct relationship between novelty processing and frontal lobe functioning.…”

Investigation of the segregated visual system

“…Similarly, it was shown in humans that the latency of the P300 component is delayed with aging (Morgan and Murphy, 2010). Likewise, cognitively high and average performers produced higher latency values with ages (Riis et al, 2008), which indicates the age-dependent factors in visual processing during normal aging. Face matching task in a PET study showed increased reaction times (Grady et al, 1994).…”