Targeted Memory Reactivation during Mind-Wandering in Younger and Older Adults

Mind-wandering (MW) is a universal cognitive process that is estimated to comprise ~30% of our everyday thoughts. Despite its prevalence, the functional utility of MW remains a scientific blind spot. The present study sought to investigate whether MW serves a functional role in cognition. Specifically, we investigated whether MW contributes to memory consolidation processes, and if age differences in the ability to reactivate episodic memories during MW may contribute to age-related declines in episodic memory. Younger and older adults encoded paired associates, received targeted reactivation cues during an interval filled with a task which promotes MW, and were tested on their memory for the cued and uncued stimuli from the initial encoding task. Thought probes were presented during the retention (MW) interval to assess participants’ thought contents. Across three experiments, we compared the effect of different cue modalities (i.e., auditory, visual) on cued recall performance, and examined both correct retrieval response times as well as accuracy. Across experiments, there was evidence that stimuli that were cued during the MW task were correctly retrieved more quickly than uncued stimuli and that this effect was more robust for younger adults than older adults. Additionally, the more MW a participant reported during the retention interval, the stronger the cueing effect they produced during retrieval. The results from these experiments are interpreted within a retrieval facilitation framework wherein cues serve to reactivate the earlier traces during MW, and this reactivation benefits retrieval speed for cued items as compared to uncued items.

The Relationship Between Hearing Loss and Cognitive Impairment in a Chinese Elderly Population: The Baseline Analysis

Objectives: The objective of the study was to investigate the association between untreated age-related hearing loss and cognitive impairment in Mandarin-speaking older adults living in China.Methods: Older adults (293; 111 males, M = 70.33 ± 4.90 years; 182 females, M = 69.02 ± 4.08 years) were recruited. All participants completed a pure tone audiometric hearing assessment, Hearing Impairment-Montreal Cognitive Assessment Test (HI-MoCA), and a computerized neuropsychology test battery (CANTAB). The Mandarin version of the De Jong Gierveld Loneliness Scale was used to measure the loneliness, and the Mandarin version of the 21-item Depression Anxiety Stress Scale (DASS-21) was used to measure the current severity of a range of symptoms common to depression, stress, and anxiety of the participants.Results: A multiple stepwise regression analysis showed that the average of four mid-frequency thresholds in the better ear was related to CANTAB Paired Associates Learning (β = 0.20, p = 0.002), and the global cognitive function score (HI-MoCA) (β = −0.25, p < 0.001). The average of three high frequencies in the better ear was significantly associated with CANTAB Delayed Matching to Sample (β = −0.16, p = 0.008), and Spatial Working Memory (β = 0.17, p = 0.003).Conclusion: The results revealed a significant relationship between age-related hearing loss and cognitive impairment in Mandarin-speaking older adults. These research outcomes have clinical implications specifically for hearing health care professionals in China and other populations that speak a tonal language, especially when providing hearing rehabilitation.

Future-relevant memories are not selectively strengthened during sleep

Overnight consolidation processes are thought to operate in a selective manner, such that important (i.e. future-relevant) memories are strengthened ahead of irrelevant information. Using an online protocol, we sought to replicate the seminal finding that the memory benefits of sleep are enhanced when people expect a future test [Wilhelm et al., 2011]. Participants memorised verbal paired associates to a criterion of 60 percent (Experiment 1) or 40 percent correct (Experiment 2) before a 12-hour delay containing overnight sleep (sleep group) or daytime wakefulness (wake group). Critically, half of the participants were informed that they would be tested again the following day, whereas the other half were told that they would carry out a different set of tasks. We observed a robust memory benefit of overnight consolidation, with the sleep group outperforming the wake group in both experiments. However, knowledge of an upcoming test had no impact on sleep-associated consolidation in either experiment, suggesting that overnight memory processes were not enhanced for future-relevant information. These findings, together with other failed replication attempts, show that sleep does not provide selective support to memories that are deemed relevant for the future.

A-167 A Comparison of Remotely Administered Verbal Paired Associates Subtests

Objective Due to the COVID-19 pandemic, many services attempted to quickly transition to a remote format. A need to validate remote delivery of neuropsychological measures arose. TestMyBrain (TMB) from the Many Brains Project has been utilizing teleneuropsychology in research since 2017. Method Volunteer research participants (N = 147, Mage = 29, Medu = 15 years, 64.7% white, 54.2% female, 83.2% right-handed, 52.1% utilized Mac Operating System) were administered TMB Verbal Paired Associates(TMBVPA) and WMS-IV Verbal Paired Associates I(VPAI) as part of a larger battery of test via zoom. The WMS-IV assessments adhered to standardization as much as possible such as limiting potential distractions. Results A correlation revealed a positive association between TMBVPA and VPAI r(150) = 0.312, p = < 0.001. A linear regression revealed that performance on the TMBVPA positively predicted performance on the VPAI F(3, 144) = 9.344, p < 0.001 accounting for 16.6% of the variability over and above known demographic variables. The rate of agreeance showed that 23.7% of TMBVPA scores were within a one score difference of the VPAI and 37.4% were within two scores. Conclusions The results suggest that the two remote administration formats may not be as congruent as originally thought. With 62.6% of scores outside of a two-point range and the low rate of agreement this suggests little real-world application of the TMBVPA. Although telepsychology has come a long way, remote neuropsychological measures may still not be a reality any time soon. Future research should compare both remote administration versions to a standardized in person administration as well as consider other factors that can influence administration formats.

Increased habitual flavonoid intake predicts attenuation of cognitive ageing in twins

Background Although the pathophysiology of cognitive decline is multifactorial, and modifiable by lifestyle, the evidence for the role of diet on cognitive function is still accumulating, particularly the potentially preventive role of constituents of plant-based foods. Methods We aimed to determine whether higher habitual intake of dietary flavonoids, key components of plant-based diets, were associated with improved cognition and medial temporal lobe volumes using three complementary approaches (longitudinal, cross-sectional and co-twin analyses). In 1126 female twins (n=224 with a 10-year follow-up of diet and cognition data) aged 18–89 years, habitual intakes of total flavonoids and seven subclasses (flavanones, anthocyanins, flavan-3-ols, flavonols, flavones, polymeric flavonoids (and proanthocyanidins separately)) were calculated using validated food frequency questionnaires. Cognition was assessed using the Cambridge Neuropsychological Test Automated Battery test. Hippocampal volumes were measured in a subset using magnetic resonance imaging (16 monozygotic-twin pairs). Statistical models were adjusted for a range of diet and lifestyle factors. Results Higher intakes of flavanones (tertile (T)3-T1=0.45, 95%CI 0.13,0.77; p=0.01) and anthocyanins (T3-T1=0.45, 95%CI 0.08,0.81; p=0.02) were associated with improvements in age-related cognition score over 10 years. In cross-sectional analysis higher intake of flavanones (T3-T1= 0.12, 95% CI 0.02, 0.21; p=0.02) and proanthocyanidins (T3-T1= 0.13, 95% CI 0.02, 0.24; p=0.02) were associated with improved paired-associates learning. Higher intake of anthocyanins was significantly associated with improved executive function (T3-T1= −0.52, 95% CI 0.19, 0.84; p=0.001) and with faster simple reaction times (T3-T1= −18.1, 95% CI −35.4, −0.7; p=0.04). In co-twin analysis, those with higher anthocyanin (2.0%, p=0.01) and proanthocyanidin (2.0%, p=0.02) intakes at baseline had the largest left hippocampal volumes after 12 years. Conclusion Small increases in habitual intake of flavonoid-rich foods (containing anthocyanins, flavanones and proanthocyanidins; equivalent to approximately two servings of oranges and blueberries per day) over long time periods have the potential to attenuate cognitive ageing.

Implicitly Learned Higher Order Associations Differentiates Recent and Remote Retrieval of Temporal Order Memory

Memory of an ordered sequence of distinct events requires encoding the temporal order as well as the intervals that separates these events. In this study, using order place association task where the animal learns to associate the location of the food pellet to the order of entry into the event arena, we probe the nature of temporal order memory in mice. In our task, individual trials, become distinct events, as the animal is trained to form unique association between entry order and a correct location. The inter-trial intervals (> 30 mins) are chosen deliberately to minimise the working memory contributions. We develop this paradigm initially using 4 order place associates and later extend it to 5 paired associates. Our results show that animals not only acquire these explicit (entry order to place) associations but also higher order associations that can only be inferred implicitly from the temporal order of these events. As an indicator of such higher order learning during the probe trail the mice exhibit predominantly prospective errors that declines proportionally with temporal distance. On the other hand, prior to acquiring the sequence the retrospective errors are dominant. Additionally, we also tested the nature of such acquisitions when temporal order CS is presented along with flavour as a compound stimulus comprising of order and flavour both simultaneously being paired with location. Results from these experiments indicate that the animal learns both order-place and flavour-place associations. Comparing with pure order place training, we find that the additional flavour in compound training did not interfere with the ability of the animals to acquire the order place associations. When tested remotely, pure order place associations could be retrieved only after a reminder training. Further higher order associations representing the temporal relationship between the events is markedly absent in the remote time.

Adult neurogenesis mediates forgetting of multiple types of memory in the rat

The formation and retention of hippocampus-dependent memories is impacted by neurogenesis, a process that involves the production of new neurons in the dentate gyrus of the hippocampus. Recent studies demonstrate that increasing neurogenesis after memory formation induces forgetting of previously acquired memories. Neurogenesis-induced forgetting was originally demonstrated in mice, but a recent report suggests that the same effect may be absent in rats. Although a general species difference is possible, other potential explanations for these incongruent findings are that memories which are more strongly reinforced become resilient to forgetting or that perhaps only certain types of memories are affected. Here, we investigated whether neurogenesis-induced forgetting occurs in rats using several hippocampus-dependent tasks including contextual fear conditioning (CFC), the Morris Water Task (MWT), and touchscreen paired associates learning (PAL). Neurogenesis was increased following training using voluntary exercise for 4 weeks before recall of the previous memory was assessed. We show that voluntary running causes forgetting of context fear memories in a neurogenesis-dependent manner, and that neurogenesis-induced forgetting is present in rats across behavioral tasks despite differences in complexity or reliance on spatial, context, or object memories. In addition, we asked whether stronger memories are less susceptible to forgetting by varying the strength of training. Even with a very strong training protocol in the CFC task, we still observed enhanced forgetting related to increased neurogenesis. These results suggest that forgetting due to neurogenesis is a conserved mechanism that aids in the clearance of memories.