Enhanced cognitive activity--over and above social or physical activity--is required to protect Alzheimer's mice against cognitive impairment, reduce Abeta deposition, and increase synaptic immunoreactivity

Although social, physical, and cognitive activities have each been suggested to reduce the risk of Alzheimer's disease (AD), epidemiologic studies cannot determine which activity or combination of activities is most important. To address this question, mutant APP transgenic AD mice were reared long-term in one of four housing conditions (impoverished, social, social+physical, or complete enrichment) from 1(1/2) through 9 months of age. Thus, a stepwise layering of social, physical, and enhanced cognitive activity was created. Behavioral evaluation in a full battery of sensorimotor, anxiety, and cognitive tasks was carried out during the final 5 weeks of housing. Only AD mice raised in complete enrichment (i.e., enhanced cognitive activity) showed: (1) protection against cognitive impairment, (2) decreased brain beta-amyloid deposition, and (3) increased hippocampal synaptic immunoreactivity. The protection provided by enhanced cognitive activity spanned multiple cognitive domains (working memory, reference learning, and recognition/identification). Cognitive and neurohistologic benefits of complete enrichment occurred without any changes in blood cytokine or corticosterone levels, suggesting that enrichment-dependent mechanisms do not involve changes in the inflammatory response or stress levels, respectively. These results indicate that the enhanced cognitive activity of complete enrichment is required for cognitive and neurologic benefit to AD mice-physical and/or social activity are insufficient. Thus, our data suggest that humans who emphasize a high lifelong level of cognitive activity (over and above social and physical activities) will attain the maximal environmental protection against AD.     

A glass full of optimism: Enrichment effects on cognitive bias in a rat model of depression

Investigations of cognitive biases in animals are conceptually and translationally valuable because they contribute to animal welfare research and help to extend and refine our understanding of human emotional disorders, where biased information processing is a critical causal and maintenance factor. We employed the "learned helplessness" genetic rat model of depression in studying cognitive bias and its modification by environmental manipulations. Using a spatial judgment task, responses to ambiguous spatial cues were assessed before and after environmental enrichment to test whether this manipulation would cause an optimistic shift in emotional state. Twenty-four congenitally helpless and nonhelpless male rats were trained to discriminate two different locations, "rewarded" versus "aversive." After successful acquisition of this spatial discrimination, cognitive bias was probed by measuring responses to three ambiguous locations. Latencies to "reach" and to actively "choose" a goal pot were recorded alongside exploratory behaviors. An overall strain difference was observed, with helpless rats displaying longer "reach" latencies than nonhelpless rats. This implies a "pessimistic" response bias in helpless rats, underscoring their depressive-like phenotype. No strain differences were observed regarding other behavioral measures. Half of the animals were then transferred to enriched cages and retested. Environmental enrichment resulted in reduced "choose" latencies in both rat strains, associating enrichment with more optimistic interpretations of ambiguous cues. Our results emphasize the suitability of cognitive bias measurement for animal emotion assessment. They extend the methodological repertoire for characterizing complex phenotypes and bear implications for animal welfare research and for the use of animal models in preclinical research.     

Effects of environmental enrichment on cognitive performance of pigs in a spatial holeboard discrimination task

This study investigated the effects of environmental enrichment on the cognitive performance of female conventional farm (growing) pigs in a spatial holeboard task. Ten pairs of littermates matched for weight were used. From each litter, one piglet was randomly assigned to a barren environment; the other was assigned to an enriched environment from 4 weeks of age. The enriched environment was double the size of the barren environment, had a floor covered with straw, a rooting area filled with peat, and one of the four different enrichment toys which were exchanged daily. Starting at 11 weeks of age, all pigs were tested in a spatial holeboard discrimination task in which 4 out of 16 holes were baited. Furthermore, basal salivary cortisol levels of all pigs were determined after the end of all testing. All pigs were able to acquire the pattern of baited holes (acquisition phase, 40 trials) and the diagonally mirrored pattern (reversal phase, 20 trials). During the acquisition phase, the reference memory performance of the enriched-housed pigs was better than that of their barren-housed littermates, i.e. they reduced visits to the unbaited set of holes. During the reversal phase, enriched-housed pigs had a better general working memory performance than the barren-housed pigs as indicated by reduced revisits to holes already visited during a trial, irrespective of whether they were of the baited or the unbaited set. The enriched-housed pigs also searched for the hidden bait faster during both phases. The environments did not affect basal salivary cortisol levels. In conclusion, environmental enrichment slightly improved the cognitive performance of pigs in a spatial learning task. We hypothesise that the long period of habituation to and testing in the holeboard acted as enrichment that partially reduced the effects of barren housing.     

Validation of a novel cognitive bias task based on difference in quantity of reinforcement for assessing environmental enrichment

Cognitive bias tasks purport to assess affective states via responses to ambiguous stimuli. We hypothesized that a novel cognitive bias task based on positive reinforcement using quantity differences would detect changes in affect in captive grizzly bears (Ursus arctos horribilis). We trained bears (n = 8) to respond differently (nose or paw touch) to two stimuli (light or dark gray cue cards), with responses counterbalanced across bears. The two cues signaled a small or large food reward, respectively. Responses to ambiguous probe stimuli (i.e., shades of gray) intermediate to the trained stimuli were classified as either ‘optimistic,’ appropriate for the larger reward, or ‘pessimistic,’ appropriate for the smaller reward. In Experiment 1, we explored the contrast in reward size necessary to detect a change in response across probe stimuli (large reward, 3 or 6 apple slices: small reward, 1 slice). We observed a change in response across probe stimuli, with no difference in response between reward-value groups, indicating that a contrast of 3:1 apple slices was sufficient to affect responses. In Experiment 2, we investigated cognitive bias after 2.1 h of exposure to enrichment items varying in attractiveness. Results were unaffected by enrichment type or time spent interacting with enrichments, indicating that the task failed to demonstrate criterion validity for comparing mood following exposure to different enrichment items. However, greater time spent pacing prior to testing was associated with ‘optimistic’ judgments. The data provide some support for use of cognitive bias tasks based on quantity differences in animal welfare assessments involving captive wildlife.     

Structural environmental enrichment and the way it is offered influence cognitive judgement bias and anxiety-like behaviours in zebrafish

Animal Cognition - Environmental enrichment in zebrafish generally reduces anxiety-related behaviours, improves learning in maze trials and increases health and biological fitness. However, certain...     

Neurogenesis decreases with age in the canine hippocampus and correlates with cognitive function

New neurons are continually produced in the adult mammalian brain from progenitor cells located in specific brain regions, including the subgranular zone (SGZ) of the dentate gyrus of the hippocampus. We hypothesized that neurogenesis occurs in the canine brain and is reduced with age. We examined neurogenesis in the hippocampus of five young and five aged animals using doublecortin (DCX) and bromodeoxyuridine (BrdU) immunostaining. The total unilateral number of new neurons in the canine SGZ and granule cell layer (GCL) was estimated using stereological techniques based upon unbiased principles of systematic uniformly random sampling. Animals received 25mg/kg of BrdU once a day for 5 days and were euthanized 9 days after the last injection. We found evidence of neurogenesis in the canine brain and that cell genesis and neurogenesis are greatly reduced in the SGZ/GCL of aged animals compared to young. We further tested the hypothesis that an antioxidant fortified food or behavioral enrichment would improve neurogenesis in the aged canine brain and neurogenesis may correlate with cognitive function. Aged animals were treated for 2.8 years and tissue was available for six that received the antioxidant food, five that received the enrichment and six receiving both treatments. There were no significant differences in the absolute number of DCX or DCX-BrdU neurons or BrdU nuclei between the treatment groups compared to control animals. The number of DCX-positive neurons and double-labeled DCX-BrdU-positive neurons, but not BrdU-positive nuclei alone, significantly correlated with performance on several cognitive tasks including spatial memory and discrimination learning. These results suggest that new neurons in the aged canine dentate gyrus may participate in modulating cognitive functions.     

Long-term enrichment enhances the cognitive behavior of the aging neurogranin null mice without affecting their hippocampal LTP

Neurogranin (Ng), a PKC substrate, is abundantly expressed in brain regions important for cognitive functions. Deletion of Ng caused severe deficits in spatial learning and LTP in the hippocampal CA1 region of mice. These Ng-/- mice also exhibit deficits in the amplification of their hippocampal signaling pathways critical for learning and memory. A short-term exposure to an enriched environment failed to improve their behavioral performances. Here, we showed that a long-term enrichment protocol for the aging mice was beneficial to the Ng-/- as well as Ng+/+ and Ng+/- mice in preventing age-related cognitive decline. Enrichment also caused an increase in the hippocampal CREB level of all three genotypes and Ng level of Ng+/+ and Ng+/- mice, but not that of alphaCaMKII or ERK. Interestingly, hippocampal slices of these enriched aging Ng-/- mice, unlike those of Ng+/+ and Ng+/- mice, did not show enhancement in the high frequency stimulation (HFS)-induced LTP in the CA1 region. It appears that the learning and memory processes in these enriched aging Ng-/- mice do not correlate with the HFS-induced LTP, which is facilitated by Ng. These results demonstrated that long-term enrichment for the aging Ng-/- mice may improve their cognitive function through an Ng-independent plasticity pathway.     

Automatic testing of cognitive performance in baboons maintained in social groups

Laboratory procedures used to study the cognitive functions of primates traditionally have involved removal of the subjects from their living quarters to be tested singly in a remote experimental room. This article presents an alternative research strategy favoring testing primates while they are maintained in their social group. The automatic learning device for monkeys (ALDM) is a computerized test system controlled by an automatic radio frequency identification of subjects. It is provided ad lib inside the social group of monkeys, for voluntary self-testing on a 24-h schedule. Nine baboons were tested with ALDM during a 7-month period. Experiments were performed to assess learning in motor control and abstract reasoning tasks. The results revealed high trial frequencies and excellent learning performance, even in tasks involving the highest cognitive complexities. A different study using ALDM with a group of 3 rhesus monkeys revealed social influences on learning. Beyond its interest for cognitive psychologists, ALDM is of interest for pharmacologists and cognitive neuroscientists working with nonhuman primates. ALDM also can serve as an enrichment tool for captive animals and may be used to study a variety of species other than primates.     

Social support and verbal interaction are differentially associated with cognitive function in midlife and older age

Social engagement is associated with healthy aging and preserved cognition. Two dimensions of engagement, verbal interactions and perceived support, likely impact cognition via distinct mechanistic pathways. We explored the cognitive benefit of each construct among enrollees (N = 1,052, mean age = 60.2 years) in the Wisconsin Registry for Alzheimer’s Prevention study, who provide neuropsychological and sociobehavioral data at two-year intervals. Outcomes included six cognitive factor scores representing key domains of executive function and memory. Key predictors included self-reported perceived social support and weekly verbal interaction. Results indicated that after adjusting for lifestyle covariates, social support was positively associated with Speed and Flexibility and that verbal interactions were associated with Verbal Learning and Memory. These findings suggest that support, which may buffer stress, and verbal interaction, an accessible, aging-friendly form of environmental enrichment, are uniquely beneficial. Both are integral in the design of clinical and community interventions and programs that promote successful aging.     

L’enrichissement entre vie professionnelle et vie personnelle : revue et programme de recherché

Work-life enrichment, defined as the transfer of resources and affects from one role to another, has long remained in the shadow of the concept of work-life conflict. Several processes for work-life enrichment, for instance instrumental and affective, have been identified. Commitment to the family role predicts work-to-family enrichment (WFE), while commitment to the work role predicts family-to-work enrichment (FWE). Gender, personality and social support are other antecedents of work-life enrichment. WFE is positively associated with job satisfaction and FEW with family satisfaction. An agenda for future research suggests conducting qualitative, longitudinal and contextualized research.     

Work–Family Enrichment Among Ghanaian Employees: the Mediating Role Between Social Support and Subjective Well-Being

This study examined the mediating roles of work-to-family enrichment and family-to-work enrichment in the relationship between work–family support and subjective well-being. Structural equation modelling results, based on cross-sectional data from 217 university employees in Ghana, showed that work support and family support were positively related to work-to-family enrichment and family-to-work enrichment. The results also showed that work-to-family enrichment mediated the relationship between work support and subjective well-being, while family-to-work enrichment mediated the relationships of work support and family support with subjective well-being. This research demonstrates that work–family enrichment provides pathways through which support resources in the work and family roles influence subjective well-being. The implications of these findings for theory and practice are discussed.     

Role resources and work–family enrichment: The role of work engagement

This article proposes a theoretical model of work-family enrichment and tests the mediating role of work engagement. The inclusion of work engagement extends prior research on work-family interface, and allows for examination of the effects of role resources (job resources, family support) on work-family enrichment. A two-wave survey was conducted among a matched sample of 786 employees in China. The model was tested with structural equation modeling techniques. The results showed that work engagement was the most proximal predictor of work-family enrichment. Work engagement fully mediated the relationship between family-friendly organizational policies and work-family enrichment, and also between job autonomy and family-work enrichment. Further, work engagement partially mediated the relationships between two job resources (supervisor support, job autonomy) and work-family enrichment, and also between family support and family-work enrichment. No difference was found in gender and marital status in the proposed model. Implications for future research and practices are discussed.     

Role resources and work–family enrichment: The role of work engagement

This article proposes a theoretical model of work-family enrichment and tests the mediating role of work engagement. The inclusion of work engagement extends prior research on work-family interface, and allows for examination of the effects of role resources (job resources, family support) on work-family enrichment. A two-wave survey was conducted among a matched sample of 786 employees in China. The model was tested with structural equation modeling techniques. The results showed that work engagement was the most proximal predictor of work-family enrichment. Work engagement fully mediated the relationship between family-friendly organizational policies and work-family enrichment, and also between job autonomy and family-work enrichment. Further, work engagement partially mediated the relationships between two job resources (supervisor support, job autonomy) and work-family enrichment, and also between family support and family-work enrichment. No difference was found in gender and marital status in the proposed model. Implications for future research and practices are discussed.     

The role of identity and work–family support in work–family enrichment and its work-related consequences

Despite growing research on the positive connections between work and family, antecedents and consequences of work–family enrichment are understudied. Using a sample of employees from a major insurance company, we assessed the relationship of (i) individual (i.e., work and family identities), (ii) family (emotional and instrumental support), and (iii) organizational (benefit use and work–family culture) antecedents to work–family and family–work enrichment. We also examined whether enrichment predicted important work outcomes including organizational commitment and turnover intentions. The strength of an individual’s identity and informal or emotional support within a domain, rather than formal or instrumental support, were associated with greater enrichment. Work–family enrichment positively predicted affective organizational commitment, and family–work enrichment negatively predicted turnover intentions. Implications for individuals and organizations wanting to foster enrichment are discussed.     

The role of identity and work-family support in work-family enrichment and its work-related consequences

Despite growing research on the positive connections between work and family, antecedents and consequences of work-family enrichment are understudied. Using a sample of employees from a major insurance company, we assessed the relationship of (i) individual (i.e., work and family identities), (ii) family (emotional and instrumental support), and (iii) organizational (benefit use and work-family culture) antecedents to work-family and family-work enrichment. We also examined whether enrichment predicted important work outcomes including organizational commitment and turnover intentions. The strength of an individual’s identity and informal or emotional support within a domain, rather than formal or instrumental support, were associated with greater enrichment. Work-family enrichment positively predicted affective organizational commitment, and family-work enrichment negatively predicted turnover intentions. Implications for individuals and organizations wanting to foster enrichment are discussed.     

工作家庭间跨界增益:逻辑主线与模型

已有工作家庭界面研究主要立足于冲突视角,近年来部分研究开始从积极视角揭示工作家庭关系的本质。工作家庭增益强调角色资源的跨界渗溢有助提升个体另一角色表现和生活品质的程度。工作家庭资源会增强个体心理资源,进而影响体验工作家庭间的跨界增益,资源的累积循环与工作家庭增益互为持续保障,跨界增益的程度受到工作家庭边界特征的调节影响。论证和提出了"角色资源累积-个体心理因素改变-跨界增益-角色评价与投入"的逻辑主线,以此构建工作家庭间角色资源跨界增益模型。     

The interactive effects of role overload and resilience on family-work enrichment and associated outcomes

ABSTRACT

Using an interactionist perspective and conservation of resources (COR) theory, this study examined the interactive effects of resilience and role overload on family-work enrichment and the outcomes of surface acting, emotional exhaustion, and job satisfaction. The model was tested using a sample of 156 full time employees who completed surveys at two time periods. As expected, resilience was positively related to family-work enrichment and family-work enrichment was negatively related to surface acting and emotional exhaustion and positively related to job satisfaction demonstrating mediating effects for family-work enrichment. Role overload moderated the positive relationship between resilience and family-work enrichment such that the relationship was weaker when role overload was high indicating a boundary condition for the favorable effects of resilience. Finally, support was found for the conditional indirect effects of resilience on surface acting, emotional exhaustion, and job satisfaction through family-work enrichment such that the relationships were weaker when role overload was high.     

工作对家庭的增益与中小学教师的工作满意度:职业认同的中介作用及其性别差异

探究工作对家庭的增益影响中小学教师工作满意度的过程机制。采用纵向设计对760名中小学教师进行问卷调查,时间点1测查人口学变量和工作对家庭的增益,时间点2测查职业认同和工作满意度。结果发现:(1)工作对家庭的增益能够显著正向预测工作满意度;(2)职业认同在工作对家庭的增益与工作满意度的关系中起部分中介作用;(3)性别对此中介过程的前半段路径具有调节作用,表现为男教师的工作对家庭的增益对职业认同的预测效力更高。结果表明:工作对家庭的增益显著影响中小学教师的工作满意度,职业认同在此影响过程中具有中介作用,且这一中介作用存在性别差异。     

Using a runway paradigm to assess the relative strength of rats’ motivations for enrichment objects

Laboratory animals should be provided with enrichment objects in their cages; however, it is first necessary to test whether the proposed enrichment objects provide benefits that increase the animals’ welfare. The two main paradigms currently used to assess proposed enrichment objects are the choice test, which is limited to determining relative frequency of choice, and consumer demand studies, which can indicate the strength of a preference but are complex to design. Here, we propose a third methodology: a runway paradigm, which can be used to assess the strength of an animal’s motivation for enrichment objects, is simpler to use than consumer demand studies, and is faster to complete than typical choice tests. Time spent with objects in a standard choice test was used to rank several enrichment objects in order to compare with the ranking found in our runway paradigm. The rats ran significantly more times, ran faster, and interacted longer with objects with which they had previously spent the most time. It was concluded that this simple methodology is suitable for measuring rats’ motivation to reach enrichment objects. This can be used to assess the preference for different types of enrichment objects or to measure reward system processes.     

AN ANALOGUE EVALUATION OF ENVIRONMENTAL ENRICHMENT: THE ROLE OF STIMULUS PREFERENCE

To evaluate the effects of environmental enrichment on stereotypic self-injurious behavior (SIB), we conducted an assessment of preference for manipulating alternative stimuli rather than engaging in SIB. First, for each of 3 participants, a functional analysis of SIB was conducted in Phase 1. Participants were selected for Phase 2 if the functional analysis showed that SIB persisted in the absence of social consequences. In Phase 2, a preference assessment was conducted in which participants were observed manipulating preferred stimuli in a free-operant format. A measure was taken of time spent manipulating each stimulus and time spent engaging in SIB. In Phase 3, environmental enrichment was evaluated using stimuli that were preferred over the target response, and alternative treatments were evaluated in the event of environmental enrichment failure. Results suggested that the free-operant preference assessment (a) predicted the efficacy or inefficacy of an environmental enrichment procedure and (b) suggested possible treatment alternatives when environmental enrichment was ineffective. Collectively, the results may provide a basis for interpreting the idiosyncratic effects of environmental enrichment and a rationale for treatment selection when behavioral function is unknown.