The gains of a 4-week cognitive training are not modulated by novelty

Randomized controlled trials of non-pharmacological interventions for healthy seniors: Effects on cognitive decline, brain plasticity and activities of daily living-A 23-year scoping review

Little is known about the simultaneous effects of non-pharmacological interventions (NPI) on healthy older adults' behavior and brain plasticity, as measured by psychometric instruments and magnetic resonance imaging (MRI). The purpose of this scoping review was to compile an extensive list of randomized controlled trials published from January 1, 2000, to August 31, 2023, of NPI for mitigating and countervailing age-related physical and cognitive decline and associated cerebral degeneration in healthy elderly populations with a mean age of 55 and over. After inventorying the NPI that met our criteria, we divided them into six classes: single-domain cognitive, multi-domain cognitive, physical aerobic, physical non-aerobic, combined cognitive and physical aerobic, and combined cognitive and physical non-aerobic. The ultimate purpose of these NPI was to enhance individual autonomy and well-being by bolstering functional capacity that might transfer to activities of daily living. The insights from this study can be a starting point for new research and inform social, public health, and economic policies. The PRISMA extension for scoping reviews (PRISMA-ScR) checklist served as the framework for this scoping review, which includes 70 studies. Results indicate that medium- and long-term interventions combining non-aerobic physical exercise and multi-domain cognitive interventions best stimulate neuroplasticity and protect against age-related decline and that outcomes may transfer to activities of daily living.

Neuronal activity and NIBS in developmental myelination and remyelination - current state of knowledge

Oligodendrocytes are responsible for myelinating central nervous system (CNS) axons. and rapid electrical transmission through saltatory conduction of action potentials. Myelination and myelin repair rely partially on oligodendrogenesis, which comprises. oligodendrocyte precursor cell (OPC) migration, maturation, and differentiation into. oligodendrocytes (OL). In multiple sclerosis (MS), demyelination occurs due to an. inflammatory cascade with auto-reactive T-cells. When oligodendrogenesis fails, remyelination becomes aberrant and conduction impairments are no longer restored. Although current disease modifying therapies have achieved results in modulating the. faulty immune response, disease progression continues because of chronic. inflammation, neurodegeneration, and failure of remyelination. Therapies have been. tried to promote remyelination. Modulation of neuronal activity seems to be a very. promising strategy in preclinical studies. Additionally, studies in people with MS. (pwMS) have shown symptom improvement following non-invasive brain stimulation. (NIBS) techniques. The aforementioned mechanisms are yet unknown and probably. involve both the activation of neurons and glial cells. Noting neuronal activity. contributes to myelin plasticity and that NIBS modulates neuronal activity; we argue. that NIBS is a promising research horizon for demyelinating diseases. We review the. hypothesized pathways through which NIBS may affect both neuronal activity in the. CNS and how the resulting activity can affect oligodendrogenesis and myelination.

Novelty-induced memory boosts in humans: The when and how

Novel information potentially signals danger or reward and behavioral and psychophysiological studies have suggested that the brain prioritizes its processing. Some effects of novelty even go beyond the stimulus itself. Studies in animals have robustly shown that exposure to novel stimulation can promote memory for information presented before or after this exposure. Research regarding effects of novelty on memory in humans is lagging, but in the last few years, several studies have emerged that suggest that memory-facilitating effects of novelty also exist in humans. Here, we provide a comprehensive overview of these studies. We identified several factors that have been shown to influence whether novelty promotes memory or not, including the timing between the novel experience and the learning events, the involvement with the novel material, and population characteristics (such as clinical diagnosis or age). Finally, we link the behavioral findings to potential neurobiological mechanisms and discuss the relevance of specific findings in light of potential clinical and educational applications that could leverage novelty to improve memory.

Novel immersive virtual reality experiences do not produce retroactive memory benefits for unrelated material

The experience of novelty can enhance memory for information that occurs close in time, even if not directly related to the experience-a phenomenon called "behavioural tagging." For example, an animal exposed to a novel spatial environment shows improved memory for other information presented previously. This has been linked to neurochemical modulations induced by novelty, which affect consolidation of memories for experiences that were encoded around the same time. Neurophysiological research in animals has shown that novelty benefits weakly encoded but not strongly encoded information. However, a benefit that is selective to weak memories seems difficult to reconcile with studies in humans that have reported that novelty improves recollection, but not familiarity. One possibility is that the novelty increases activity in hippocampus, which is also associated with processes that enable recollection. This is consistent with another prediction of behavioural tagging theory, namely that novelty only enhances consolidation of information that converges on the same neuronal population. However, no study has directly explored the relationship between encoding strength and retrieval quality (recollection versus familiarity). We examined the effects of exposure to a novel immersive virtual reality environment on memory for words presented immediately beforehand, under either deep or shallow encoding tasks, and by testing both recall memory immediately, and recognition memory with remember/know instructions the next day. However, Bayes factors showed no evidence to support the behavioural tagging predictions: that novelty would improve memory, particularly for shallowly encoded words, and this improvement would differentially affect familiarity versus recollection.

Effects of exploring a novel environment on memory across the lifespan

Exploration of a novel environment has been shown to promote memory formation in healthy adults. Studies in animals have suggested that such novelty-induced memory boosts are mediated by hippocampal dopamine. The dopaminergic system is known to develop and deteriorate over the lifespan, but so far, the effects of novelty on memory across the lifespan have not yet been investigated. In the current study, we had children, adolescents, younger, and older adults (n = 439) explore novel and previously familiarized virtual environments to pinpoint the effects of spatial novelty on declarative memory in humans across different age groups. After exploration, words were presented while participants performed a deep or shallow encoding task. Incidental memory was quantified in a surprise test. Results showed that participants in the deep encoding condition remembered more words than those in the shallow condition, while novelty did not influence this effect. Interestingly, however, children, adolescents and younger adults benefitted from exploring a novel compared to a familiar environment as evidenced by better word recall, while these effects were absent in older adults. Our findings suggest that the beneficial effects of novelty on memory follow the deterioration of neural pathways involved in novelty-related processes across the lifespan.

Artificial Cognitive Systems Applied in Executive Function Stimulation and Rehabilitation Programs: A Systematic Review

This article presents a systematic review of studies on cognitive training programs based on artificial cognitive systems and digital technologies and their effect on executive functions. The aim has been to identify which populations have been studied, the characteristics of the implemented programs, the types of implemented cognitive systems and digital technologies, the evaluated executive functions, and the key findings of these studies. The review has been carried out following the PRISMA protocol; five databases have been selected from which 1889 records were extracted. The articles were filtered following established criteria, to give a final selection of 264 articles that have been used for the purposes of this study in the analysis phase. The findings showed that the most studied populations were school-age children and the elderly. The most studied executive functions were working memory and attentional processes, followed by inhibitory control and processing speed. Many programs were commercial, customizable, gamified, and based on classic tasks. Some more recent initiatives have begun to incorporate user-machine interfaces, robotics, and virtual reality, although studies on their effects remain scarce. The studies recognize multiple benefits of computerized neuropsychological stimulation and rehabilitation programs for executive functions in different age groups, but there is a lack of studies in specific population sectors and with more rigorous research designs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13369-022-07292-5.

A Randomized Controlled Trial Study of a Multimodal Intervention vs. Cognitive Training to Foster Cognitive and Affective Health in Older Adults

Research over the past few decades has shown the positive influence that cognitive, social, and physical activities have on older adults’ cognitive and affective health. Especially interventions in health-related behaviors, such as cognitive activation, physical activity, social activity, nutrition, mindfulness, and creativity, have shown to be particularly beneficial. Whereas most intervention studies apply unimodal interventions, such as cognitive training (CT), this study investigates the potential to foster cognitive and affective health factors of older adults by means of an autonomy-supportive multimodal intervention (MMI). The intervention integrates everyday life recommendations for six evidence-based areas combined with psychoeducational information. This randomized controlled trial study compares the effects of a MMI and CT on those of a waiting control group (WCG) on cognitive and affective factors, everyday life memory performance, and activity in everyday life. Three groups, including a total of 119 adults aged 65–86 years, attended a 5- or 10-week intervention. Specifically, one group completed a 10-week MMI, the second group completed 5-week of computer-based CT followed by a 5-week MMI, whereas the third group paused before completing the MMI for the last 5 weeks. All participants completed online surveys and cognitive tests at three test points. The findings showed an increase in the number and variability of activities in the everyday lives of all participants. Post hoc analysis on cognitive performance of MMI to CT indicate similar (classic memory and attention) or better (working memory) effects. Furthermore, results on far transfer variables showed interesting trends in favor of the MMI, such as increased well-being and attitude toward the aging brain. Also, the MMI group showed the biggest perceived improvements out of all groups for all self-reported personal variables (memory in everyday life and stress). The results implicate a positive trend toward MMI on cognitive and affective factors of older adults. These tendencies show the potential of a multimodal approach compared to training a specific cognitive function. Moreover, the findings suggest that information about MMI motivates participants to increase activity variability and frequency in everyday life. Finally, the results could also have implications for the primary prevention of neurocognitive deficits and degenerative diseases.

Auditory Cognitive Training Improves Brain Plasticity in Healthy Older Adults: Evidence From a Randomized Controlled Trial

The number of older adults is increasing globally. Aging is associated with cognitive and sensory decline. Additionally, declined auditory performance and cognitive function affect the quality of life of older adults. Therefore, it is important to develop an intervention method to improve both auditory and cognitive performances. The current study aimed to investigate the beneficial effects of auditory and cognitive training on auditory ability and cognitive functions in healthy older adults. Fifty healthy older adults were randomly divided into four training groups—an auditory-cognitive training group (AC training; n = 13), an auditory training group (A training; n = 13), a cognitive training group (C training; n = 14), and an active control group (n = 12). During the training period, we reduced the sound intensity level in AC and A training groups and increase training task difficulty in AC, A, and C training groups based on participants’ performance. Cognitive function measures [digit-cancelation test (D-CAT); logical memory (LM); digit span (DS)], auditory measures [pure-tone audiometry (PTA)], and magnetic resonance imaging (MRI) scans were performed before and after the training periods. We found three key findings. First, the AC training group showed difference between other training groups (A, C, and active control training groups) in regional gray matter volume (rGMV) in the right dorsolateral prefrontal cortex, the left inferior temporal gyrus (L. ITG), the left superior frontal gyrus, the left orbitofrontal cortex, the right cerebellum (lobule 7 Crus 1). Second, the auditory training factor groups (ATFGs, the AC and A training groups) improved auditory measures and increased the rGMV and functional connectivity (FC) in the left temporal pole compared to the non-ATFGs (the C training group and active control group). Third, the cognitive training factor groups (CTFGs; the AC and C training groups) showed statistically significant improvement in cognitive performances in LM and D-CAT compared to the non-CTFGs (the A training group and active control group). Therefore, the auditory training factor and cognitive training factor would be useful in enhancing the quality of life of older adults. The current AC training study, the plasticity of the brain structure was observed after 4 weeks of training.

Novelty exposure induces stronger sensorimotor representations during a manual adaptation task

Active exploration of novel spatial environments enhances memory for subsequently presented explicit, declarative information in humans. These effects have been attributed to novelty promoting dopamine release via mesolimbic dopaminergic pathways in the brain. As procedural motor learning has been linked to dopamine as well, we predict that novelty effects extend to this domain. To test this hypothesis, the present study examined whether spatial novelty exploration benefits subsequent sensorimotor adaptation. Participants explored either two different virtual environments (i.e., novelty condition; n = 210) or two identical environments (i.e., familiar condition; n = 253). They then performed a manual adaptation task in which they had to adapt joystick movements to a visual perturbation. We assessed the rate of adaptation following the introduction of this perturbation, and the rate of deadaptation following its removal. While results showed reliable adaptation patterns and similar adaptation rates across both conditions, individuals in the novelty condition showed slower deadaptation. This suggests that exposure to spatial novelty induced stronger sensorimotor representations during adaptation, potentially through novelty-induced dopaminergic effects in mesocortical and/or nigrostriatal pathways. Novelty exposure may be employed to promote motor learning on tasks that require precision movements in altered sensory contexts, for example, in astronauts moving in microgravity or patients with impaired motor processing.

Age-related iron accumulation and demyelination in the basal ganglia are closely related to verbal memory and executive functioning

Age-related cognitive decline has been linked to alterations of the dopaminergic system and its subcortical trajectories. Recent work suggests a critical role of iron accumulation within the basal ganglia (BG) in verbal memory performance, and increased iron levels have been related to demyelination. However, the specificity of age-related iron increases with respect to cognitive functions remains unclear. Therefore, we investigated the interplay of age, cognitive performance, and structural integrity of the BG. In total, 79 healthy older participants underwent a broad cognitive assessment (fluid and crystallized intelligence, verbal and numeric memory, processing speed, executive functions) and structural MRI. As expected, performance in most cognitive tests had a negative relationship with age. Moreover, BG grey matter volume and magnetization transfer (MT, indicative of myelin) decreased, and R2* (indicative of iron) increased with age. Importantly, R2* and demyelination negatively correlated with verbal memory and executive functions. Within the SN/VTA, age correlated negatively with MT, but there was no clear evidence in favor of a relationship between behavior and R2* or MT. Our results suggest that age-related increases in iron and demyelination within the BG, which are part of a fronto-striatal network, not only impact on verbal memory but also executive functions.

Working memory training: Taking a step back to retool and create a bridge between clinical and neuroimaging research methods

Improvements in patient outcomes and mortality after brain injury alongside increasing ageing population have resulted in an increasing need to develop cognitive interventions for individuals experiencing changes in their cognitive function. One topic of increasing research interest is whether cognitive functions such as attention, memory and executive functioning can be improved through the use of working memory training interventions. Both clinical and neuroimaging researchers are working to evidence this, but their efforts rarely come together. We discuss here several issues that may be hindering progress in this area, including the tools researchers utilize to measure cognition, the choice between employing active or passive control groups, the focus on transfer effects at the expense of well-characterized training effects, and the overall lack of neuroimaging studies in individuals with neurological disorders. We argue that the only way to advance the field is to build bridges between the disciplines of clinical neuropsychology and cognitive neuroscience. We suggest a multi-level framework to validate the efficacy of working memory interventions and other forms of cognitive training that combine both clinical and neuroimaging approaches. We conclude that in order to move forward we need to form multidisciplinary teams, employ interdisciplinary methods, brain imaging quality rating tools and build national and international collaborations based on open science principles.

Effects of active exploration on novelty-related declarative memory enhancement

Exploration of novel environments has reliably been shown to enhance learning in rodents. More recently, these effects have been replicated in humans using virtual reality: Memory is enhanced after exploration of novel compared to familiar virtual environments. However, exploration of a novel versus familiar environment differs in another aspect. Navigating familiar territory can rely more on habits, while navigating new territory requires active decision-making. This difference in choices could contribute to the positive effects of novelty exploration on memory. In this study, we aimed to investigate this possibility. Participants familiarized with a virtual environment (day 1) and were exposed to this environment again (day 2 or 3) and to a novel environment (day 2 or 3). Participants either actively explored the environments or were passively exposed to the exploration behavior of another participant in virtual reality. After exposure to the environment, participants performed a word-learning task and filled out questionnaires regarding virtual presence and the novelty seeking personality trait. Mixed models suggested that memory performance was higher after participants actively explored versus were passively exposed to a novel environment, while these effects were reversed for a familiar environment. Bayesian statistics provided further weak evidence that memory performance was influenced by the interaction between novelty and exposure type. Taken together, our findings suggest that active exploration may contribute to novelty-induced memory benefits, but future studies need to confirm this finding.

The gains of a 4-week cognitive training are not modulated by novelty

Cognitive training should not only improve performance of the trained task, but also untrained abilities. Exposure to novelty can improve subsequent memory performance, suggesting that novelty exposure might be a critical factor to promote the effects of cognitive training. Therefore, we combined a 4‐week working memory training with novelty exposure. Neuropsychological tests and MRI data were acquired before and after training to analyze behavior and changes in gray matter volume, myelination, and iron levels. In total, 83 healthy older humans participated in one of three groups: Two groups completed a 4‐week computerized cognitive training of a two‐back working memory task, either in combination with novel or with familiarized nature movies. A third group did not receive any training. As expected, both training groups showed improvements in task specific working memory performance and reaction times. However, there were no transfer or novelty effects on fluid intelligence, verbal memory, digit‐span, and executive functions. At the neural level, no significant micro‐ or macrostructural changes emerged in either group. Our findings suggest that working memory training in healthy older adults is associated with task‐specific improvements, but these gains do not transfer to other cognitive domains, and it does not lead to structural brain changes.