Independent contributions of fMRI familiarity and novelty effects to recognition memory and their stability across the adult lifespan

Abstract

The impact of age on the neural correlates of familiarity-driven recognition memory has received relatively little attention. Here, the relationships between age, the neural correlates of familiarity, and memory performance were investigated using an associative recognition test in young, middle-aged and older participants. Test items comprised studied, rearranged (items studied on different trials) and new word pairs. fMRI ‘familiarity effects’ were operationalized as greater activity for studied test pairs incorrectly identified as ‘rearranged’ than for correctly rejected new pairs. The reverse contrast was employed to identify ‘novelty’ effects. Estimates of familiarity strength were slightly but significantly lower for the older relative to the younger group. With the exception ofoneregion indorsal medial prefrontal cortex, fMRI familiarity effects (which were identified in medial and lateral parietal cortex, dorsal medial and left lateral prefrontal cortex, and bilateral caudate among other regions) did not differ significantly with age. Age-invariant ‘novelty effects’ were identified in the anterior hippocampus and the perirhinal cortex. When entered into the same regression model, familiarity and novelty effects independently predicted familiarity strength across participants, suggesting that the two classes of memory effect reflect functionally distinct mnemonic processes. It is concluded that the neural correlates of familiarity-based memory judgments, and their relationship with familiarity strength, are largely stable across much of the healthy adult lifespan.

Dissociation between the neural correlates of recollection and familiarity in the striatum and hippocampus: Across-study convergence

“…The data from these participants are not included in the analyses presented here. The findings for the recollection contrasts in these studies have been described previously, both singly (Elward et al, 2015; de Chastelaine et al, 2016; Wang et al 2016) and together (King et al, 2015), but the findings for the familiarity/novelty contrasts have been previously reported only for Experiment 2 (de Chastelaine et al, in press). Comparisons of striatal recollection and familiarity effects are reported here for the first time.…”

“…Accuracy data for each of the three experiments have been fully described previously (Elward et al, 2015; de Chastelaine et al, 2016, in press; Wang et al 2016; see also King et al, 2015). In each case estimates of recollection and familiarity were robustly above chance.…”

“…By contrast, input to the dorsal striatum derives largely from lateral PFC, a region that consistently demonstrates robust familiarity-related activity (e.g. Yonelinas et al, 2005; Johnson et al, 2013; de Chastelaine et al, in press). How the striatum exploits or augments these different memory signals are key questions for the future.…”

“…Data from three previously published studies (Elward et al, 2015; de Chastelaine et al, 2016, in press; Wang et al 2016) were analyzed, each of which employed a sample of healthy, right-handed young adults (aged 18 – 30 yrs), with Ns of 24, 36 and 28 in experiments 1, 2 and 3 respectively (see King et al, 2015, for description of analyses of this data-set in respect of recollection-related modulation of functional connectivity). All subjects gave informed consent prior to participation and were compensated for their time.…”

“…Here we take advantage of three independent data sets (described originally in Elward et al, 2015; de Chastelaine et al, 2016, in press; Wang et al 2016) to examine whether memory judgments based on recollection or familiarity are associated with dissociable patterns of striatal activity. The three studies employed memory tests that differed markedly in their operationalization of recollection and familiarity (see Table 1 and Methods) and used diverse experimental materials.…”