Age-related differences in working memory: ERPs reveal age-related delays in selection- and inhibition-related processes

Abstract

Faulty inhibition is implicated in age-related working memory decline. ERP signs of selection and inhibition of items in working memory (WM) are, respectively, a cue-locked parietal positivity (~ 350 ms) and a probe-locked frontal negativity (~ 520 ms). To determine when in the older age range differences in selective and inhibitory processes might occur, ERPs were recorded in a WM task from 20 young (20–28), 20 young-old (60–70) and 20 old-old (71–82) adults. A 4-digit display was followed by a cue indicating which 2 of 4 digits were relevant. Proactive interference (PI), the reaction time difference between a matching and non-matching to-be-ignored digit was larger, relative to the young, in both older groups. Compared to the young, both the cue- and probe-locked activities were prolonged in the older groups. Although there were no topographic differences among the age groups, the prolonged PI and associated ERPs suggest a relative age-related deficit in inhibition.

Effects of proactive interference on non-verbal working memory

“…These results are compatible with the effects reported in studies of verbal WM (Bissett et al 2009; Bunge et al 2001; Eich et al 2014; Jonides et al 1998; Nee and Jonides 2008; Nee et al 2007; Nelson et al 2003; Smith et al 2011; Yi and Friedman 2014; Zhang et al 2003). Moreover, we found that nameability and color moderate these effects on ER performance, such that more accurate performance was observed with HN and colored objects than with LN and gray objects.…”

“…A large body of research has examined the effects and resolution of PI in verbal WM (Bissett et al 2009; Bunge et al 2001; Eich et al 2014; Jonides et al 1998; Nee and Jonides 2008; Nee et al 2007; Nelson et al 2003; Smith et al 2011; Yi and Friedman 2014; Zhang et al 2003). By contrast, studies using non-verbal material are scarce, and it remains unclear whether the effects of PI are domain-general or whether they differ across the visual and verbal domains.…”

Event-Related Brain Potentials in the Study of Inhibition: Cognitive Control, Source Localization and Age-Related Modulations

“…With respect to age-related differences, they identified a delayed latency for this activity in the 71-82 age-range group . Similar to Yi and Friedman's (2011) finding, Yi and Friedman (2014) identified an N450 at the probe stage that was larger for "intrusion probes" compared with "non-intrusion probes", which likely reflects processes that enable proactive interference resolution. They identified a delayed latency for this activity in both of the older adults' groups.…”

“…This inhibition age-related decline has also been identified in proactive interference studies (Tays et al 2008;Yi and Friedman 2014). Tays et al (2008) used high density electrophysiology to examine differences between older (N=18; M=72.4 years old, range 65-87; 14 women) and young (N=16; M=20 years old, range 18-26; 10 women) adults in a Sternberg Task.…”

“…The authors interpreted the absence of the frontal negativity in older adults as an indication of a proactive interference processing deficit in older adults. Yi and Friedman (2014) studied these age-related differences in greater detail via comparisons of young adults (from Yi and Friedman's 2011 study) to two groups of older adults, which included a group with older adults ranging in age from 60 to 70 years old (N=20; 15 women) and a yet older group ranging age from 71 to 82 years old (N=20; 15 women) adults. They used the cued Sternberg's Task from Yi and Friedman's (2011) study and examined both cue-and probe-related inhibition ERP correlates.…”