The relationships between age, associative memory performance, and the neural correlates of successful associative memory encoding

Abstract

Using fMRI, subsequent memory effects (greater activity for later remembered than later forgotten study items) predictive of associative encoding were compared across samples of young, middle-aged and older adults (total n = 136). During scanning, participants studied visually presented word pairs. In a later test phase, they discriminated between studied pairs, ‘rearranged’ pairs (items studied on different trials) and new pairs. Subsequent memory effects were identified by contrasting activity elicited by study pairs that went on to be correctly judged intact or incorrectly judged rearranged. Effects in the hippocampus were age-invariant and positively correlated across participants with associative memory performance. Subsequent memory effects in the right IFG were greater in the older than the young group. In older participants only, both left and, in contrast to prior reports, right IFG subsequent memory effects correlated positively with memory performance. We suggest that the IFG is especially vulnerable to age-related decline in functional integrity, and that the relationship between encoding-related activity in right IFG and memory performance depends on the experimental context.

The neural correlates of recollection and retrieval monitoring: Relationships with age and recollection performance

“…In either case, one might anticipate identifying relationships between neural activity and memory performance that are unique to, or stronger in older than in young individuals. We have recently reported such findings from the encoding phase of the present study (de Chastelaine et al, 2015, 2016). To anticipate the present results, in contrast to those findings, here we find no evidence that relationships between individual differences in retrieval-related activity and memory performance are modified by age.…”

“…As in our prior reports (de Chastelaine et al, 2011, 2015, 2016; see also King et al, 2015), recollection accuracy was indexed as the difference between the proportion of intact test pairs correctly endorsed as intact (associative hits) and the proportion of rearranged test pairs incorrectly judged intact (associative false alarms). Table 2 provides a summary of associative recognition performance for each age group.…”

“…Data from the encoding phase of this experiment were reported in two prior publications (de Chastelaine et al, 2015, 2016), where additional description of the experimental procedures and methods can be found.…”

“…It has been proposed (e.g., Cabeza et al, 2002; Reuter-Lorenz & Park, 2014), for example, that performance in older adults benefits from age-related neural reorganization (neural ‘compensation’ or ‘scaffolding’). In addition, it is possible that, with increasing age, performance becomes increasingly sensitive to individual differences in the functional integrity of regions vulnerable to aging (de Chastelaine et al, 2011, 2016). In either case, one might anticipate identifying relationships between neural activity and memory performance that are unique to, or stronger in older than in young individuals.…”

“…We elected to investigate associative memory because it is strongly dependent on episodic recollection (e.g., Mickes et al, 2010) and thus is a relatively ‘process-pure’ memory test. In addition, associative memory is highly sensitive to age (Old & Naveh-Benjamin, 2008), and the neural correlates of the encoding of associative information are already known to differ according to age (de Chastelaine et al, 2011, 2015, 2016; Miller et al, 2008). Three prior fMRI studies examining the effects of age on the neural correlates of episodic retrieval also employed an associative memory procedure (Oedekoven et al, 2013; Dulas & Duarte, 2016; Wang & Giovanello, 2016).…”