Underlie Age Differences Research Articles

Older adults preserve audiovisual integration through enhanced cortical activations, not by recruiting new regions.

Effective interactions with the environment rely on the integration of multisensory signals: Our brains must efficiently combine signals that share a common source, and segregate those that do not. Healthy ageing can change or impair this process. This functional magnetic resonance imaging study assessed the neural mechanisms underlying age differences in the integration of auditory and visual spatial cues. Participants were presented with synchronous audiovisual signals at various degrees of spatial disparity and indicated their perceived sound location. Behaviourally, older adults were able to maintain localisation accuracy. At the neural level, they integrated auditory and visual cues into spatial representations along dorsal auditory and visual processing pathways similarly to their younger counterparts but showed greater activations in a widespread system of frontal, temporal, and parietal areas. According to multivariate Bayesian decoding, these areas encoded critical stimulus information beyond that which was encoded in the brain areas commonly activated by both groups. Surprisingly, however, the boost in information provided by these areas with age-related activation increases was comparable across the 2 age groups. This dissociation-between comparable information encoded in brain activation patterns across the 2 age groups, but age-related increases in regional blood-oxygen-level-dependent responses-contradicts the widespread notion that older adults recruit new regions as a compensatory mechanism to encode task-relevant information. Instead, our findings suggest that activation increases in older adults reflect nonspecific or modulatory mechanisms related to less efficient or slower processing, or greater demands on attentional resources.

Developmental Shifts in Amygdala Activity during a High Social Drive State.

Amygdala abnormalities characterize several psychiatric disorders with prominent social deficits and often emerge during adolescence. The basolateral amygdala (BLA) bidirectionally modulates social behavior and has increased sensitivity during adolescence. We tested how an environmentally-driven social state is regulated by the BLA in adults and adolescent male rats. We found that a high social drive state caused by brief social isolation increases age-specific social behaviors and increased BLA neuronal activity. Chemogenetic inactivation of BLA decreased the effect of high social drive on social engagement. High social drive preferentially enhanced BLA activity during social engagement; however, the effect of social opportunity on BLA activity was greater during adolescence. While this identifies a substrate underlying age differences in social drive, we then determined that high social drive increased BLA NMDA GluN2B expression and sensitivity to antagonism increased with age. Further, the effect of a high social drive state on BLA activity during social engagement was diminished by GluN2B blockade in an age-dependent manner. These results demonstrate the necessity of the BLA for environmentally driven social behavior, its sensitivity to social opportunity, and uncover a maturing role for BLA and its GluN2B receptors in social engagement.SIGNIFICANCE STATEMENT Social engagement during adolescence is a key component of healthy development. Social drive provides the impetus for social engagement and abnormalities underlie social symptoms of depression and anxiety. While adolescence is characterized by transitions in social drive and social environment sensitivity, little is known about the neural basis for these changes. We found that amygdala activity is uniquely sensitive to social environment during adolescence compared with adulthood, and is required for expression of heightened social drive. In addition, the neural substrates shift toward NMDA dependence in adulthood. These results are the first to demonstrate a unique neural signature of higher social drive and begin to uncover the underlying factors that heighten social engagement during adolescence.

Brain Structural-Behavioral Correlates Underlying Grooved Pegboard Test Performance Across Lifespan

This study aims to provide the first brain structural-behavioral correlates underlying age differences in Grooved Pegboard Test (GPT) performance after adjusting for gender, education, quality of life, mental health, and anthropometric variables. We report the data of 210 right-handed participants (20- to 80-year old), who underwent behavioral assessments including GPT, Trail Making Test, and stop-signal task. Magnetic resonance images were acquired to investigate the structural-behavioral correlates of age differences in GPT performance. Age differences in GPT performance were positively associated with visuomotor tracking performance and negatively associated with widespread brain structural measures, including white matter tracts (e.g., commissure, radiation, and association fibers) and gray matter regions in frontal and cingulate regions, parietal, and temporal lobes.

Age-related decline in emotional perspective-taking: Its effect on the late positive potential.

Aging is associated with changes in cognitive and affective functioning, which likely shape older adults' social cognition. As the neural and psychological mechanisms underlying age differences in social abilities remain poorly understood, the present study aims to extend the research in this field. To this purpose, younger (n = 30; Mage = 26.6), middle-aged (n = 30; Mage = 48.4), and older adults (n = 29; Mage = 64.5) performed a task designed to assess affective perspective-taking, during an EEG recording. In this task, participants decided whether a target facial expression of emotion (FEE) was congruent or incongruent with that of a masked intervener of a previous scenario, which portrayed a neutral or an emotional scene. Older adults showed worse performance in comparison to the other groups. Regarding electrophysiological results, while younger and middle-aged adults showed higher late positive potentials (LPPs) after FEEs congruent with previous scenarios than after incongruent FEEs, older adults had similar amplitudes after both. This insensitivity of older adults' LPPs in differentiating congruent from incongruent emotional context-target FEE may be related to their difficulty in generating information about others' inner states and using that information in social interactions.

Age-Related Differences in Savoring Across Adulthood: The Role of Emotional Goals and Future Time Perspective

Healthy aging is related to increased happiness along with attention and memory biases for positive information, which has led some researchers to suggest that older adults may be better at savoring (i.e., emotion regulation strategies that up-regulate or maintain positive affect). Paradoxically, preliminary empirical findings suggest that savoring is maintained across adulthood or may even decrease with age, but this research has relied solely on the use of self-reported questionnaires. The current study further investigated savoring in adulthood (N = 119; age range = 18–83 years) using self-reported questionnaires and an experimental savoring task where participants were instructed to up-regulate positive affect about a previous positive event. Emotional goals and motivations that might underlie age differences in savoring (hedonic motivation, ideal affect, and future time perspective) were also examined. Overall, results suggest that older adults savor less than adults of younger ages. Older adults reported lower trait savoring using self-reported measures. Similarly, young adults and middle-aged adults randomly assigned to the experimental savoring task experienced more positive affect than those assigned to a neutral control task, but older adults did not experience these same emotional benefits. Relations between age and savoring were mediated by an age-related decrease in hedonic motivation and the desire to experience high arousal positive affect. Together, these findings offer new evidence that older adults may savor less than young adults and middle-aged adults, which may be partially due to age-related differences in emotional goals.

Blood-brain barrier and cerebral blood flow: Age differences in hemorrhagic stroke

Neonatal stroke is similar to the stroke that occurs in adults and produces a significant morbidity and long-term neurologic and cognitive deficits. There are important differences in the factors, clinical events and outcomes associated with the stroke in infants and adults. However, mechanisms underlying age differences in the stroke development remain largely unknown. Therefore, treatment guidelines for neonatal stroke must extrapolate from the adult data that is often not suitable for children. The new information about differences between neonatal and adult stroke is essential for identification of significant areas for future treatment and effective prevention of neonatal stroke. Here, we studied the development of stress-induced hemorrhagic stroke and possible mechanisms underlying these processes in newborn and adult rats. Using histological methods and magnetic resonance imaging, we found age differences in the type of intracranial hemorrhages. Newborn rats demonstrated small superficial bleedings in the cortex while adult rats had more severe deep bleedings in the cerebellum. Using Doppler optical coherent tomography, we found higher stress-reactivity of the sagittal sinus to deleterious effects of stress in newborn vs. adult rats suggesting that the cerebral veins are more vulnerable to negative stress factors in neonatal vs. adult brain in rats. However, adult but not newborn rats demonstrated the stroke-induced breakdown of blood brain barrier (BBB) permeability. The one of possible mechanisms underlying the higher resistance to stress-related stroke injures of cerebral vessels in newborn rats compared with adult animals is the greater expression of two main tight junction proteins of BBB (occludin and claudin-5) in neonatal vs. mature brain in rats.

Holistic Processing of Faces May Underlie Age Differences in Performance on Taiwanese Face Memory Test (TFMT)

Holistic Processing of Faces May Underlie Age Differences in Performance on Taiwanese Face Memory Test (TFMT)

The influence of monetary incentives on context processing in younger and older adults: an event-related potential study.

Recent evidence has indicated that neuronal activity related to reward anticipation benefits subsequent stimulus processing, but the effect of penalties remains largely unknown. Since the dual-mechanisms-of-control theory (DMC; Braver & Barch, Neuroscience and Biobehavioral Reviews, 26, 809-81, 2002) assumes that temporal differences in context updating underlie age differences in cognitive control, in this study we investigated whether motivational cues (signaling the chance to win or the risk to lose money, relative to neutral cues) preceding context information in a modified AX-CPT paradigm influence the temporal stages of context processing in younger and older adults. In the behavioral data, younger adults benefited from gain cues, evident in their enhanced context updating, whereas older adults exhibited slowed responding after motivational cues, irrespective of valence. Event-related potentials (ERPs) revealed that the enhanced processing of motivational cues in the P2 and P3b was mainly age-invariant, whereas age-differential effects were found for the ERP correlates of context processing. Younger adults showed improved context maintenance (i.e., a larger negative-going CNV), as well as increased conflict detection (larger N450) and resolution (indicated by a sustained positivity), whenever incorrect responding would lead to a monetary loss. In contrast, motivationally salient cues benefited context representations (in cue-locked P3b amplitudes), but increased working memory demands during response preparation (via a temporally prolonged P3b) in older adults. In sum, motivational valence and salience effects differentially modulated the temporal stages of context processing in younger and older adults. These results are discussed in terms of the DMC theory, recent findings of emotion regulation in old age, and the relationship between cognitive and affective processing.

Age Differences in the Processing of Context Information

The dual mechanisms of control theory (DMC; Braver & Barch, 2002 ) assumes that age-related changes in the temporal structure of context processing underlie age differences in numerous cognitive control tasks. Younger adults usually exhibit a proactive control mode, characterized by cue-related context updating, while older adults show a reactive control mode, updating information when interference is detected. This study aimed at determining whether age differences in electrophysiological correlates of context updating in a pro-and reactive manner are independent of individual differences in task performance. To this end, younger and older adults were split into four groups according to their updating efficiency in behavioral data. Nineteen younger and 18 older adults completed a modified AX-Continuous-Performance Task ( Lenartowicz, Escobedo-Quiroz, & Cohen, 2010 ) in which correct responses to probes were either dependent (c-dep) or independent (c-indep) on a preceding contextual cue. Analysis of the behavioral data showed no differences in context updating when performance was matched, that is, between low performing younger and high performing older adults. However, low performing younger adults showed larger cue-locked parietal P3b amplitudes on c-dep than c-indep trials, indicating c-dep trials to require context updating to a larger extent, while high performing older adults exhibited a specific control strategy and continuously updated context information, as reflected in comparable P3b amplitudes on c-dep and c-indep trials. The persistent age effect in the P3b when controlling for performance differences suggests context updating to be fundamental to cognitive aging. High performing in contrast to low performing older adults also showed a larger negative N450 to ambiguous probes on c-dep trials associated with conflict detection. According to the DMC, this finding suggests late conflict detection at the time interference is detected, indicative of a reactive control style particular in high performing elderly.

Age-related dedifferentiation and compensatory changes in the functional network underlying face processing

Recent evidence has shown that older adults fail to show adaptation in the right fusiform gyrus (FG) to the same face presented repeatedly, despite accurate detection of the previously presented face. We used functional magnetic resonance imaging to investigate whether this phenomenon is associated with age-related reductions in face specificity in brain activity and whether older adults compensate for these face-processing deficiencies by increasing activity in other areas within the face-processing network, or outside this network. A comparison of brain activity across multiple stimulus categories showed that, unlike young adults who engaged a number of brain regions specific to face processing, older adults generalized these patterns of activity to objects and houses. Also, young adults showed functional connectivity between the right FG and its homologous region during face processing, whereas older adults did not engage the left FG but showed a functional connection between the right FG and left orbitofrontal cortex. Finally, this frontotemporal functional connection was activated more strongly in older adults who performed better on a face-matching task (done outside of the scanner), suggesting increased involvement of this functional link for successful face recognition with increasing age. These findings suggest that 2 neural mechanisms, dedifferentiation and compensatory neural recruitment, underlie age differences in face processing.

Adult Age Differences in Learning on a Sequentially Cued Prediction Task

Much of adaptive behavior relies on the ability to learn and generate predictions about relationships in the environment. Research on aging suggests both that there is an age deficit in the ability to learn sequential relationships and that this deficit in learning could underlie age differences reported in many decision-making tasks. This article introduces the Triplets Prediction Task (TPT) to investigate the learning of sequential relationships that underlies adaptive behavior. In the TPT, participants see 2 successive visual cues and then predict which target will follow. Unknown to participants, there is a predictive relationship between the first cue and the target such that each of 4 cues predicts 1 of 4 targets 85% of the time. Although both age groups demonstrated learning on this task, an age deficit in learning appeared early and performance differences persisted throughout training. There was also evidence of age differences in the learning systems engaged during the task. These results are consistent with previous studies of learning and prediction, and they support the growing literature showing adult age differences in decision making from experience.

Age‐related differences in working memory deficits during nicotine withdrawal

Nicotine withdrawal is associated with subtle working memory deficits that predict subsequent relapse. We examined the neural substrates underlying these processes in treatment-seeking smokers, and explored the moderating influence of age on abstinence-induced alterations in brain activity and performance. Sixty-three smokers participated in two blood oxygen level-dependent (BOLD) functional magnetic resonance imaging scans while performing a visual N-back task on two separate occasions: smoking as usual and after 24 hours of biochemically confirmed abstinence (order counterbalanced). Abstinence (versus smoking) led to reduced accuracy, slower median correct response time and reduced BOLD signal change in the three a priori regions of interest: medial frontal/cingulate gyrus and right and left dorsolateral prefrontal cortex. Significant age × session effects were found for BOLD signal change in all three regions, as well as for withdrawal and craving; for all measures, abstinence effects were attenuated in smokers aged ≥50 years compared with those <50 years old. These results suggest that abstinence effects on neurocognitive function may be more pronounced for younger smokers, and may indicate a new avenue for research exploring mechanisms underlying age differences in smoking cessation success.

Ageing effects on path integration and landmark navigation

Navigation abilities show marked decline in both normal ageing and dementia. Path integration may be particularly affected, as it is supported by the hippocampus and entorhinal cortex, both of which show severe degeneration with ageing. Age differences in path integration based on kinaesthetic and vestibular cues have been clearly demonstrated, but very little research has focused on visual path integration, based only on optic flow. Path integration is complemented by landmark navigation, which may also show age differences, but has not been well studied either. Here we present a study using several simple virtual navigation tasks to explore age differences in path integration both with and without landmark information. We report that, within a virtual environment that provided only optic flow information, older participants exhibited deficits in path integration in terms of distance reproduction, rotation reproduction, and triangle completion. We also report age differences in triangle completion within an environment that provided landmark information. In all tasks, we observed a more restricted range of responses in the older participants, which we discuss in terms of a leaky integrator model, as older participants showed greater leak than younger participants. Our findings begin to explain the mechanisms underlying age differences in path integration, and thus contribute to an understanding of the substantial decline in navigation abilities observed in ageing.

The two-component model of memory development, and its potential implications for educational settings

We recently introduced a two-component model of the mechanisms underlying age differences in memory functioning across the lifespan. According to this model, memory performance is based on associative and strategic components. The associative component is relatively mature by middle childhood, whereas the strategic component shows a maturational lag and continues to develop until young adulthood. Focusing on work from our own lab, we review studies from the domains of episodic and working memory informed by this model, and discuss their potential implications for educational settings. The episodic memory studies uncover the latent potential of the associative component in childhood by documenting children's ability to greatly improve their memory performance following mnemonic instruction and training. The studies on working memory also point to an immature strategic component in children whose operation is enhanced under supportive conditions. Educational settings may aim at fostering the interplay between associative and strategic components. We explore possible routes towards this goal by linking our findings to recent trends in research on instructional design.

Emotion complexity and emotion regulation across adulthood

This research used data from a study on daily emotional experience in adulthood to examine the associations between age, emotion complexity, and emotion regulation. Data were drawn from a study of daily stress that included 239 participants ranging in age from 18 to 89 from North Central Florida. Two indicators of emotion complexity were considered: emotion differentiation and the co-occurrence of positive and negative affect. Emotion regulation was assessed in terms of individuals' likelihood of maintaining adaptive emotion states. There were no age differences in adults' co-occurrence of positive and negative emotions. In contrast to theories suggesting age would be associated with greater emotion complexity, the findings revealed that older adults had lower differentiation scores than younger adults. Age was also associated with more adaptive patterns of emotion regulation. Specifically, older adults persisted in low negative states and moved out of high negative states more readily than younger adults. Finally, neuroticism, self-concept incoherence, mean daily stress, and emotion complexity were associated with emotion regulation. Notably, adults who reported a greater mix of positive and negative affect moved out of high negative affect states more rapidly than adults with lower co-occurrence scores. This finding is in keeping with a growing body of work suggesting that positive affect promotes recovery from negative affect. Overall, the findings suggest that although emotion complexity is associated with emotion regulation, it does not appear to be a key factor underlying age differences in emotion regulation.

Mechanisms underlying age differences in dopaminergic drug sensitivity

Adolescence is a critical developmental period during which neuropsychiatric disorders emerge and drug abuse often begins. Adolescents exhibit unique responses to both illicit and therapeutic drugs; for example, showing blunted behavioral responses to indirect dopamine (DA) agonists like amphetamine and cocaine. These behavioral differences may be mediated by changes in the organization and sensitivity of the DA system during adolescence. To test the hypothesis that the functional sensitivity of D1‐like and D2‐like DA receptors changes with age, adolescent and adult male rats were given increasing doses of the D2‐like agonist quinpirole, the adenylyl cyclase‐coupled D1 agonist SKF83822, or the phospholipase C‐coupled D1 agonist SKF83959. Rats were monitored for locomotor and stereotypic behaviors, after which brains were collected and stored for analysis of immediate early gene (IEG) expression via in situ hybridization for c‐fos and arc mRNA. Behaviorally, quinpirole is more efficacious during adolescence, whereas SKF83822 is more potent in adulthood. Preliminary IEG analysis suggests that unique sets of neural circuitry are activated by quinpirole in the adolescent, with neural stress systems playing an important role. These data imply that DA system dynamics change during adolescence, with important implications for pharmacotherapy design and use in this population.

Explaining age differences in temporal working memory.

To determine the cognitive mechanisms underlying age differences in temporal working memory (WM), the authors examined the contributions of item memory, associative memory, simple order memory, and multiple item memory, using parallel versions of the delayed-matching-to-sample task. Older adults performed more poorly than younger adults on tests of temporal memory, but there were no age differences in nonassociative item memory, regardless of the amount of information to be learned. In contrast, a combination of associative and simple order memory, both of which were reduced in older adults, completely accounted for age-related declines in temporal memory. The authors conclude that 2 mechanisms may underlie age differences in temporal WM, namely, a generalized decline in associative ability and a specific difficulty with order information.

A Review of Age Differences in Psychological Adjustment to Breast Cancer

This article reviews recent literature on age differences in psychological adjustment to breast cancer. Overall, studies have shown that older women experience less psychological distress in terms of anxiety, depression, and posttraumatic stress symptoms. Age differences in health status, treatment provision, social support, and other life circumstances may contribute to differential patient adjustment. Coping also may mediate the relationship between age and affective responses, but the confounding of coping and distress in widely used inventories precludes definitive conclusions. Future research should explore the contextual mechanisms underlying age differences in adjustment.

Aging and memory for music: A review.

People of all ages enjoy listening to music, yet most research inmusical development has concentrated on infancy through childhood. Our recent research program examined various aspects of music cognition younger (ages 18 through 30) and older adults (ages 60 through 80) with varying amounts of musical experience. The studies investigated the independent and combined influences of age and experience on a wide assortment of long and short-term memory tasks. Results showed that some musical tasks reflect the same age-related declines as seen nonmusical tasks, and musical training does not reduce these age-related declines. In other tasks, experience differences were larger than age differences; some cases, age differences were nonexistent. The analysis considers how aging and experience may affect different aspects of cognition, and the paper concludes by pointing out the many musical activities that even nonmusical seniors are well equipped to succeed at and enjoy. Why study age differences memory for music? If shear neglect of a topic can justify it being studied, then surely our question is answered. The voluminous literature on age differences memory includes only a handful of studies that use musical materials. Recent reviews of this Ii terature by Anderson and Craik (2000), Balota, Dolan, and Duchek (2000), and Backman, Small, and Wahlin (2001 ) do not mention music, and another review by Zacks, Hasher, & Li (2000) mentions only one relevant study. Similarly, only rarely do music cognition journals carry articles concerning age differences. It is clear that we know little about music cognition old age. But neglect of the problem is only one reason why it needs to be addressed. Several additional reasons come readily to mind. First, everyday observation suggests that older adults enjoy and participate musical activities. Musical activities have an overall positive effect among people suffering from dementia (Koger, Chapin, & Brotons, 1999) as well among their healthy peers (Darrough & Boswell, 1992). A survey by Gibbons ( 1982) found that 84% of a sample of 152 healthy elderly people wished to improve their musical skills. MUsiC therapists have published suggestions for music programs with the elderly (Bell, 1987; Clair, 1996; Glassman, 1983; Hintz, 2000). However, the dearth of research makes it difficult for therapists to really understand the musical capabilities of their elderly clients. Among the questions that basic research on music and aging can help answer is whether a person can maintain or even improve her or his skill level if given musical training, and to what extent musical programs for older adults should emphasize exposure to familiar vs. new pieces and styles. second, music may be an ideal domain to study the aging of domainspecific processes compared to the aging of general-purpose operations of learning and memory. For example, researchers currently are interested changes short-term, or working memory with age. Not only are investigators studying the nature of age differences working memory itself, they also are examining whether deficits working memory processes may underlie age differences long-term memory, prose comprehension, and other cognitive domains. Yet tests of working memory almost always use verbal or visuospatial stimuli, and, for this reason, the dominant model of working memory (Baddeley, 1986) distinguishes only three basic components: a phonological loop, a visuospatial scratchpad, and a central executive. The familiar experience of having a tune in our head suggests the operation of a melodic (Berz, 1995) that might show age differences and have functional importance for a variety of music-related.activities including learning new tunes, recalling old tunes, and, perhaps most important, simply appreciating music. To examine this loop across the adult lifespan is certainly a task that is well worth our time. …

Ageing and Memory: Mechanisms Underlying Age Differences in Performance

Abstract. Although it is widely believed that memory generally declines with age, in fact, age decrements occur for most, but not for all, types of memory. Age differences are always found for free and cued recall but are rarely found for picture recognition, implicit memory and measures of verbal ability. Understanding the conditions under which age differences occur and when they do not across memory domain is a challenging puzzle for cognitive ageing researchers. The hypothesis adopted here is that the magnitude of age‐related decrements in memory function across different domains of memory can be accounted for by the amount of processing resource or mental effort required to encode and retrieve information. Different conceptualisations of processing resource are explored and supporting data are reviewed.