Search

Clinical evidence indicates that serotonin-1A receptor (5-HT1AR) gene polymorphisms are associated with anxiety disorders and deficits in cognition. In animal models, exercise (Ex) and environmental enrichment (EE) can change emotionality-related behaviours, as well as enhance some aspects of cognition and hippocampal neurogenesis. We investigated the effects of Ex and EE (which does not include running wheels) on cognition and anxiety-like behaviours in wild-type (WT) and 5-HT1AR knock-out (KO) mice. Using an algorithm-based classification of search strategies in the Morris water maze, we report for we believe the first time that Ex increased the odds for mice to select more hippocampal-dependent strategies. In the retention probe test, Ex (but not EE) corrected long-term spatial memory deficits displayed by KO mice. In agreement with these findings, only Ex increased hippocampal cell survival and BDNF protein levels. However, only EE (but not Ex) modified anxiety-like behaviours, demonstrating dissociation between improvements in cognition and innate anxiety. EE enhanced hippocampal cell proliferation in WT mice only, suggesting a crucial role for intact serotonergic signalling in mediating this effect. Together, these results demonstrate differential effects of Ex vs EE in a mouse model of anxiety with cognitive impairment. Overall, the 5-HT1AR does not seem to be critical for those behavioural effects to occur. These findings will have implications for our understanding of how Ex and EE enhance experience-dependent plasticity, as well as their differential impacts on anxiety and cognition.

Antagonist and long-lasting environmental manipulations (EM) have successfully induced or reduced the stress responses and quality of life of zebrafish. For instance, environmental enrichment (EE) generally reduces anxiety-related behaviours and improves immunity, while unpredictable chronic stress (UCS) and aquarium-related stressors generate the opposite effects. However, there is an absence of consistency in outcomes for some EM, such as acute exposure to stressors, social enrichment and some items of structural enrichment. Therefore, considering intraspecies variation (sex, personality, and strain), increasing intervention complexity while improving standardisation of protocols and contemplating the possibility that EE may act as a mild stressor on a spectrum between too much (UCS) and too little (standard conditions) stress intensity or stimulation, would reduce the inconsistencies of these outcomes. It would also help explore the mechanism behind stress resilience and to standardise EM protocols. Thus, this review critically analyses and compares knowledge existing over the last decade concerning environmental manipulations for zebrafish and the influences that sex, strain, and personality may have on behavioural, physiological, and fitness-related responses.

Behavioral theories of depression posit that depression results from the environment not adequately reinforcing non-depressive behaviors. One commonly used treatment based on the behavioral model of depression is Behavioral Activation. While many implementations of Behavioral Activation emphasize social interactions, there is limited empirical investigation into the contribution of specific facets of social engagement in the behavioral model of depression. Fear of intimacy, an indicator of willingness to engage in specific types of social interactions, may play an important role in understanding at a functional level what aspects of social engagement are important in behavioral activation. The current study (N = 353) proposes a model, anchored in functional outcomes of behavioral interactions, to explain the development and utilization of social support as environmental enrichment. The proposed model accounted for 55% of the variance of depressive symptoms. Findings were consistent with a model where fear of intimacy was directly and indirectly associated with depression via activation, social support, and environmental enrichment. Notably, social support was not directly associated with depression. Findings suggest the importance of incorporating vulnerable self-disclosure in behavioral activation treatments to foster environmental enrichment.

When an object conditioned stimulus (CS) is paired with a food unconditioned stimulus (US), anticipatory goal-directed action directed at the US location (goal tracking) is accompanied by behavior directed at the object CS (sign tracking). Sign-tracking behavior appears to be compulsive and habit-like and predicts increased vulnerability to the addictive potential of drugs in animal models. A large body of the literature also suggests that environmental enrichment protects against the development of addiction-prone phenotypes. Thus, we investigated whether compulsive-like sign tracking develops in environmentally enriched rats trained directly in their enriched home environment. We demonstrate that adolescent enriched-housed male Sprague-Dawley rats readily sign track a 5% ethanol bottle CS in their home environment and at a rate higher than adolescent standard-housed rats. We also show that enriched adolescent rats sign track less than enriched adult-trained rats and that acute isolation stress affects sign- and goal-tracking performance of adolescents and adults differently. Sign tracking increased more in the adult than the adolescent rats. Whereas the younger rats showed a decrease in goal tacking after the final stressor manipulation, the adults showed increased goal tracking. Our results are consistent with recent studies, which suggest that although sign tracking performance is compulsive-like, it is not as inflexible and habit-like as previously assumed. Testing in an enriched home environment with object CSs having greater affordance than "neutral" lever CSs may provide greater ecological relevance for investigating the development and expression of adaptive and compulsive-like behaviors in translational research.

Objectives The concept analysis of environmental enrichment aims to clarify the meaning of the term contributing to a shared understanding of its use in healthcare and future research studies. Environmental enrichment has implications in health promotion in children's development and healthy aging in the general population. Methods A literature search using PubMed and CINAHL databases on environmental enrichment was conducted to identify the uses of the term from various disciplines. The keywords are "environmental enrichment", "socialization", "physical activity", "cognitive stimulation", and "experience-dependent". Human studies from 2000 to 2020 were included in the search. Results Availability of green spaces, neighborhood safety, walkability to community centers, and accessibility of community resources are antecedents of environmental enrichment. Defining attributes are positive stimulation, interpersonal interaction, and physical engagement. The consequences of environmental enrichment are improved cognitive functioning in children, decline in memory impairment, and reduced risk of developing dementia in the elderly. Conclusion Engaging and counseling patients, family members, and the community in adverse effects of a deprived environment and the benefits of an enriched environment is a vital tenet of the nursing discipline. Understanding the optimum amount of positive stimulation, interpersonal interaction duration, and frequency are needed in future research.

Rearing rodents in an enriched environment (EE), with increased sensory stimulations and social interactions, is a well-established model for naturally increasing neural activity. It is well-known that EE-rearing of rodents from adolescence or during adulthood leads to extensive biochemical, morphological, electrophysiological and behavioral changes. Here, we examine the effects of EE-rearing from birth on adult behavior. Through a battery of assays, we found that mice EE-reared from birth had better acquisition and consolidation of memory, in both aversive-based fear conditioning and reward-based contextual association tasks. Moreover, EE-reared mice showed reduced anxiety in novel environments and enhanced social interactions. Together, these results demonstrated that EE-rearing from birth significantly improved motor ability, learning and memory and sociability, while reducing anxiety. A better understanding of how early environmental influences affect behavior is not only important for understanding neural circuit wiring, but also provides insight into developing more effective intervention programs for neurodevelopmental disorders.

Much environmental enrichment for laboratory animals is intended to enhance animal welfare and normalcy by providing stimulation to reduce ‘boredom’. Behavioural manifestations of boredom include restless sensation-seeking behaviours combined with indicators of sub-optimal arousal. Here, we explored whether these signs could be reduced by extra daily play opportunity in laboratory ferrets (Mustela putorius furo). Specifically, we hypothesised that playtime would reduce restlessness, aggression, sensation-seeking and awake drowsiness, even 24 h later in the home-cage. Female ferrets (n = 14) were group-housed in enriched multi-level cages. Playtime involved exploring a room containing a ball pool, paper bags, balls containing bells, and a familiar interactive human for 1 h. This was repeated on three consecutive mornings, and on the fourth, home-cage behaviour was compared between ferrets which had experienced the playtime treatment versus control cage-mates which had not. Their investigation of stimuli (positive = mouse odour or ball; ambiguous = empty bottle or tea-strainer; and negative = peppermint or bitter apple odour) was also recorded. We then swapped treatments, creating a paired experimental design. Ferrets under control conditions lay awake with their eyes open and screeched significantly more, but slept and sat/stood less, than following playtime. They also contacted negative and ambiguous stimuli for significantly longer under control conditions than following playtime; contact with positive stimuli showed no effects. Attempts to blind the observer to treatments were unsuccessful, so replication is required, but the findings suggest that playtime may have reduced both sub-optimal arousal and restless sensation-seeking behaviour, consistent with reducing boredom.

Studies over the last 40 years have mainly investigated sleep structure changes as a result of wake duration, in the frame of the classical sleep regulation theories. However, wake intervals of the same duration can profoundly differ in their intensity, which actually reflects the degree of cognitive and physical activity. Data on how sleep can be modified by wake intensity changes (initially sparse and of little consistence) have become much more substantial, especially in the frame of the intense research debate on sleep-memory relationships. Our aim is to examine the vast repertoire of sleep modifications that depend on waking cognitive manipulations, highlighting the sleep features that appear most affected. By systematically addressing this issue, we want to set the basis for future research exploring both the specific nature of the mechanisms involved and the applicative psychosocial and clinical fall-outs, in terms of possible behavioural interventions for sleep quality improvement.

Human studies suggest that healthy social relationships benefit cognition, yet little is known about the underlying neural mechanisms of this protective effect. In rodents, studies on acute isolation and environmental enrichment (EE) confirm the importance of social exposure. Despite the widely recognized importance of sociality, however, rodent models have yet to explore the independent contributions of social housing divorced of other forms of enrichment. This study dissociates the effects of social and physical enrichment on spatial learning and memory from adulthood to old age. Rats were placed in either single or group housing, provided with ample enrichment, and tested at three time points on several phases/versions of the Barnes maze (BM) (standard, retention probes, variable location, and reversal). We found that sustained social housing enhanced cognitive flexibility, as evidenced by superior acquisition of task set (standard BM), adaptability to a new task set (variable BM), and improved reversal learning (reversal BM). Long-term retention (BM retention probes) of spatial memory was unaffected by housing conditions. Recent studies from our lab, including this report, are the first to show that social housing confers cognitive benefits beyond those of physical enrichment. Importantly, our experimental design is ideal for exploring the neural underpinnings of this socially induced cognitive protection. Understanding how sociality influences cognition will be invaluable to translational models of aging, neuropsychiatric disease, and neurological injury.

Background/Objectives Environmental enrichment (EE) is a physiological model to investigate brain-fat interactions. We previously discovered that EE activates the hypothalamic-sympathoneural adipocyte (HSA) axis via induction of brain-derived neurotrophic factor (BDNF), thus leading to sympathetic stimulation of white adipose tissue (WAT) and an anti-obesity phenotype. Here, we investigate whether PTEN acts as a downstream mediator of the HSA axis in the EE. Methods Mice were housed in EE for 4- and 16-week periods to determine how EE regulates adipose PTEN. Hypothalamic injections of adeno-associated viral (AAV) vectors expressing BDNF and a dominant negative form of its receptor were performed to assess the role of the HSA axis in adipose PTEN upregulation. A β-blocker, propranolol, and a denervation agent, 6-hydroydopamine, were administered to assess sympathetic signaling in the observed EE-PTEN phenotype. To determine whether inducing PTEN is sufficient to reproduce certain EE adipose remodeling, we overexpressed PTEN in WAT using an AAV vector. To determine whether adipose PTEN is necessary for the EE-mediated reduction in adipocyte size, we injected a rAAV vector expressing Cre recombinase to the WAT of adult PTENflox mice and placed the mice in EE. Results EE upregulated adipose PTEN expression, which was associated with suppression of AKT and ERK phosphorylation, increased hormone-sensitive lipase (HSL) phosphorylation, and reduced adiposity. PTEN regulation was found to be controlled by the HSA axis—with the hypothalamic BDNF acting as the upstream mediator—and dependent on sympathetic innervation. AAV-mediated adipose PTEN overexpression recapitulated EE-mediated adipose changes including suppression of AKT and ERK phosphorylation, increased HSL phosphorylation, and reduced adipose mass, whereas PTEN knockdown blocked the EE-induced reduction of adipocyte size. Conclusions These data suggest that adipose PTEN responds to environmental stimuli and serves as downstream mediator of WAT remodeling in the EE paradigm, resulting in decreased adipose mass and decreased adipocyte size.

The Rat Park studies are classic experiments in addiction neuroscience, yet they have not been successfully replicated directly and several serious methodological criticisms have been raised. However, the conceptual reproducibility of the Rat Park studies is supported by both contemporaneous and subsequent research. Contemporaneous research on social and environmental enrichment frequently found social isolation rendered rats less sensitive to the effects of drugs of abuse. The Rat Park studies therefore confirmed the importance of social and environmental enrichment and extended this literature to suggest that enrichment reduced opioid consumption. Subsequent studies have also demonstrated social and environmental enrichment reduces drug consumption. However, there are also several papers reporting no effects of enrichment (or ‘negative’ results) and caveats from studies that show genes, age, sex and drug of abuse are all important parameters. While the Rat Park studies did not use methods that are reliable by current standards, enrichment has been shown to reliably reduce opioid consumption and this effect can generalise to other drugs of abuse.

Environmental enrichment is essential for the well-being of zoo animals. Recent advances in sensor and video technologies may contribute to improvements in enrichment in terms of their flexibilities and time constraints. The purpose of this study was to investigate whether interactive movie art can be used as a form of environmental enrichment. We implemented interactive movies designed by a professional artist, a visual art aiming to reflect naturalistic forest habitat, in an indoor chimpanzee enclosure at Kyoto City Zoo in Japan. Motion-tracking sensors embedded in buoys were installed at several locations around the indoor enclosure; the chimpanzees could change the movie contents by physically interacting with these objects. We recorded behaviors by observing entire troop of chimpanzees (six) between March 16 and 20, 2020 (control condition), then recorded behaviors when the interactive movie was presented (experimental condition) between March 21 and 29, 2020. Behaviors were recorded via direct observations and video recordings to examine any changes after the installation of interactive art. The chimpanzees spent more time in the indoor enclosures during the experimental condition than during the control condition. Activity budgets did not change substantially during the study period. There was no evidence of habituation to the movie during the study period. Three chimpanzees, including two young chimpanzees, interacted with the movie more frequently than the others; these young chimpanzees occasionally showed playful expressions when interacting with the movie and exhibited different reactivities to the movie scenes. These results demonstrate, first, that the interactive art did not negatively affect chimpanzee behavior, and second, that some of the chimpanzees indeed showed positive responses to the art. This study, therefore, introduces a novel possibility for environmental enrichment in zoos, involving a collaboration between science and art. published

Strongly affecting human and animal physiology, sounds and vibration are critical environmental factors whose complex role in behavioral and brain functions necessitates further clinical and experimental studies. Zebrafish are a promising model organism for neuroscience research, including probing the contribution of auditory and vibration stimuli to neurobehavioral processes. Here, we summarize mounting evidence on the role of sound and vibration in zebrafish behavior and brain function, and outline future directions of translational research in this field. With the growing environmental exposure to noise and vibration, we call for more active use of zebrafish models for probing neurobehavioral and bioenvironmental consequences of acute and long-term exposure to sounds and vibration in complex biological systems.

Funder: Career Support Fund, University of Cambridge (awarded to RM, supporting RM and EGP), Animal cognition covers various mental processes including perception, learning, decision-making and memory, and animal behavior is often used as a proxy for measuring cognition. Animal cognition/behavior research has multiple benefits; it provides fundamental knowledge of animal biology and evolution but can also have applied conservation and welfare applications. Zoos provide an excellent yet relatively untapped resource for animal cognition research, because they house a wide variety of species-many of which are under threat-and allow close observation and relatively high experimental control compared to the wild. Multi-zoo collaboration leads to increased sample size and species representation, which in turn leads to more robust science. However, there are salient challenges associated with zoo-based cognitive research, which are animal-based (e.g., small sample sizes at single zoos, untrained/unhabituated subjects, side effects) and human-based (e.g., time restrictions, safety concerns, and perceptions of animals interacting with unnatural technology or apparatus). We aim to increase the understanding and subsequent uptake of animal cognition research in zoos, by transparently outlining the main benefits and challenges. Importantly, we use our own research (1) a study on novelty responses in hornbills, and (2) a multi-site collaboration called the "ManyBirds" Project to demonstrate how challenges may be overcome. These potential options include using "drop and go" apparatuses that require no training, close human contact or animal separation. This study is aimed at zoo animal care and research staff, as well as external researchers interested in zoo-based studies.

Early life environment influences the development of various aspects of social behavior, particularly during sensitive developmental periods. We studied how challenges in the early postnatal period or (early) adolescence affect pro-social behavior. To this end, we designed a lever-operated liberation task, to be able to measure motivation to liberate a trapped conspecific (by progressively increasing required lever pressing for door-opening). Liberation of the trapped rat resulted either in social contact or in liberation into a separate compartment. Additionally, a condition was tested in which both rats could freely move in two separate compartments and lever pressing resulted in social contact. When partners were not trapped, rats were more motivated to press the lever for opening the door than in either of the trapped configurations. Contrary to our expectations, the trapped configuration resulted in a reduced motivation to act. Early postnatal stress (24 h maternal deprivation on postnatal day 3) did not affect behavior in the liberation task. However, rearing rats from early adolescence onwards in complex housing conditions (Marlau cages) reduced the motivation to door opening, both in the trapped and freely moving conditions, while the motivation for a sucrose reward was not affected.

To examine the influences of community-enriched environment on the cognitive trajectories of the elderly in China, using panel data of 10,057, 3994, 2387, and 1749 older persons aged 65–104 years of the 2005, 2008, 2011, and 2014 waves from the Chinese Longitudinal Health Longevity Survey (CLHLS) and a growth curve model, the authors analyzed the changing trend of elderly people’s cognitive abilities with age. The influences of community-enriched environments on cognitive abilities were also investigated. Results show that when all the factors are out of consideration except age, for an older person aged 82.5 years, as he/she grows one year older, his/her cognitive abilities will be reduced by 0.139 points, while for one aged 92.5 years, they will be reduced by 0.199 points, which means cognitive abilities decline rapidly as the individuals grow older. The elderly people from communities with enriched environments have higher cognitive levels and slower declining speeds of cognitive abilities than the other elderly people, proving the long-term ability of such environments to facilitate cognitive abilities. An increase in the stimulation of the enriched environment is needed to prevent or slow down the degeneration of cognitive abilities.

Background Replacement, reduction and refinement, the 3R principles, provide a framework to minimize the use and suffering of animals in science. In this context, we aimed to determine the actual perception that individuals working with laboratory rodents in biomedical research have on animal welfare and on their interaction with the animals, as well as how they perceive its impact on their social relations. To this end, we designed an anonymous on-line survey for people working with rodents, at three responsibility levels, in Spain. Results Of the 356 participants, 239 were women (67 %); 263 were researchers (74 %), and 93 animal facility staff (26 %), of which 55 were caretakers/technicians (15 %), and 38 welfare officer/veterinarians (11 %). Animal facility staff indicated environmental enrichment to be a universal practice. About half of the participants reported that, in their opinion, animals suffer “little to none” or “minor” stress and pain. Animal caretakers/technicians and researchers perceived higher levels of stress and pain than welfare officers/veterinarians. Participants judged decapitation the most unpleasant method to kill rodents, whereas anaesthetic overdose was the least one. A sizable proportion − 21 % of animal caretakers/technicians and 11.4 % of researchers - stated that they were never given the choice not to euthanize the rodents they work with. Overall, women reported higher interactions with animals than men. Nevertheless, we could detect a significant correlation between time spent with the animals and interaction scores. Notably, 80 % of animal facility staff and 92 % of researchers rarely talked about their work with laboratory rodents with people outside their inner social circle. Conclusions Overall, the participants showed high awareness and sensitivity to rodent wellbeing; animal facility staff reported a similar perception on welfare questions, independently of their category, while researchers, who spent less time with the animals, showed less awareness and manifested lower human-animal interaction and less social support. Regarding the perception on social acceptance of laboratory animal work, all groups were cautious and rarely talked about their job, suggesting that it is considered a sensitive issue in Spain.

Since the 1950s, researchers have examined how differences in the social and asocial environment affect learning in rats, mice, and, more recently, a variety of other species. Despite this large body of research, little has been done to synthesize these findings and to examine if social and asocial environmental factors have consistent effects on cognitive abilities, and if so, what aspects of these factors have greater or lesser impact. Here, we conducted a systematic review and meta-analysis examining how different external environmental features, including the social environment, impact learning (both speed of acquisition and performance). Using 531 mean-differences from 176 published articles across 27 species (with studies on rats and mice being most prominent) we conducted phylogenetically corrected mixed-effects models that reveal: (i) an average absolute effect size |d| = 0.55 and directional effect size d = 0.34; (ii) interventions manipulating the asocial environment result in larger effects than social interventions alone; and (iii) the length of the intervention is a significant predictor of effect size, with longer interventions resulting in larger effects. Additionally, much of the variation in effect size remained unexplained, possibly suggesting that species differ widely in how they are affected by environmental interventions due to varying ecological and evolutionary histories. Overall our results suggest that social and asocial environmental factors do significantly affect learning, but these effects are highly variable and perhaps not always as predicted. Most notably, the type (social or asocial) and length of interventions are important in determining the strength of the effect.

Cognitive reserve is originally an epidemiological concept that encompasses individual abilities to cope with changes. It is considered the result of a balance between processes of cellular damage and repair, and its description raised much interest in predicting and preventing cognitive decline in aging and Alzheimer's disease (AD). In this study, we discussed the concept of cognitive reserve considering the recent definition of AD as a biological continuum and suggest that the protection of cognitive reserve may result from efficient synaptic plasticity mechanisms. Despite pathological changes of AD appearing very early during life, long before the onset of cognitive symptoms, different variables act together to keep repair mechanisms effective guaranteeing successful aging if environmental enrichment is maintained.

Concerns are often raised about the impact that playing video games may have on cognition and behavior, whether gameplay is intense and protracted as with competitive Esports or whether it is more casual gameplay. Work in our lab and others, however, has shown that at least some classes of games can improve memory function. In particular, playing immersive 3D games that provide rich experiences and novelty improve memory on tasks that rely upon the hippocampus in effects that mirror the effects of “environmental enrichment” in numerous rodent studies. Our goal in the present study was to determine whether even modest amounts of gameplay (~30 min/day for 4 weeks) would result in improved memory performance in middle-aged adults. Not only is this demographic potentially highly receptive to gaming (they make up a significant portion of Esports viewers and of game players), but interventions in middle age may be a prime time for reducing later age-related cognitive decline. Here, we found that the benefits in middle age paralleled effects previously observed in young adults as playing Minecraft, showing improved memory performance on a hippocampal dependent memory task.

This chapter focuses on the informal learning opportunities that arise from environmental enrichment and what their consequences are for the animal. Environmental enrichment typically involves the addition of novel stimuli to a captive animal's environment in an attempt to improve animal welfare for example, the provision of toys to an enclosure. All of social, occupation or cognitive, physical, sensory, and nutritional categories of environmental enrichment if managed properly can provide informal learning opportunities for animals. The arrival of internet video calling has created a number of extremely interesting social enrichment opportunities; for example, the ability of animals of the same species to interact visually and auditory in a remote manner. In the case of cognitive enrichment, food is often used to lure the animal into using the enrichment; it is then less clear whether the primary reinforcement is the food or the learning opportunity.

Early postnatal experience has a profound influence on the development of organisms. In this integration, we provide a novel framework of the neurobehavioral pathways through which positive early postnatal experience acts to enhance adult reward sensitivity. The heterogeneity of the construct of reward and the underlying neurotransmitter systems (i.e., dopamine in incentive reward, opioids in consummatory reward, and oxytocin in orienting the reward systems to social cues) are first described as a means of organizing the discussion. Then, for each neurotransmitter system, their early postnatal ontogenesis is depicted for identifying potential sensitive periods for the effects of early experience. This is followed by the presentation of a model of the neurobehavioral foundation of two main forms of positive early postnatal experience that, with their essential components – novelty and positive tactile stimulation, facilitate the development of incentive and consummatory reward systems. Next, a detailed analysis of the major effects of positive early prewean and postwean experience on the neural and behavioral functioning of each neurotransmitter system is reviewed. The data support the neurobehavioral model presented, which theorizes that essential components of positive early experience enhance incentive and consummatory reward sensitivities through early activation of particular neural pathways. These activity-dependent effects are sustained via structural modifications of underlying neural circuitries.

Theory and empirical findings predict that individuals in a negative affective state are more sensitive to unexpected reward loss and less sensitive to unexpected reward gain compared to individuals in a neutral or positive affective state. We explore the use of sensitivity to reward shifts measured during successive contrast tasks as an indicator of affect in zebrafish (Danio rerio). In line with the assumption that exposure to rewarding stimuli induces a relatively positive affective state compared to exposure to stimuli that they do not prefer, we confirmed that zebrafish prefer enriched over barren environments, suggesting that the enriched environment is associated with positive affective states. We trained individuals to swim down a channel for food rewards of differing value and then presented them with unexpected increases or decreases in reward value. Contrary to our hypothesis, individuals conditioned to a high-value reward continued swimming at the same speed when reward value was downshifted, thus showing no successive negative contrast effect and appearing insensitive to reward loss. Individuals whose rewards were upshifted gradually increased their speed, but did not display successive positive contrast effects typical of sensitivity to reward gains. In both cases, housing type did not result in differences in swim time. One potential explanation is that goal-directed control of behaviour is necessary for an animal to show a successive contrast response to unexpected reward gain or loss, and the behaviour of zebrafish in this task was under habitual control, perhaps due to over-training. If so, refinements to task design and training procedures will allow further progress with this assay.

Background:Aging is an unavoidable, physiological process that reduces the complexity and the plasticity of the synaptic contacts in Central Nervous System (CNS), having profound implications for human well-being. The term “cognitive reserve” refers to central cellular adaptations that augment the resilience of human brain to damage and aging. The term “Cognitive training” indicates the cultural, social and physical stimulations proposed as add-on therapy for the cure of central neurological diseases. “Cognitive training” reinforces the “cognitive reserve” permitting to counteract brain impairments and rejuvenating synaptic complexity. The research has begun investigating the clinical impact of the “cognitive training” in aged people, but additional work is needed to definitively assess its effectiveness. In particular, there is a need to understand, from a preclinical point of view, whether “cognitive training” promotes compensatory effects or, alternatively, if it elicits genuine recovery of neuronal defects. Although the translation from rodent studies to the clinical situation could be difficult, the results from pre-clinical models are of high clinical relevance, since they should allow a better understanding of the effects of environmental interventions in aging-associated chronic derangements in mammals.Conclusion:Data in literature and the recent results obtained in our laboratory concerning the impact of environmental stimulation on the presynaptic release of noradrenaline, glutamate and gamma amino butyric acid (GABA) suggest that these neurotransmitters undergo different adaptations during aging and that they are differently tuned by “cognitive training”. The impact of “cognitive training” on neurotransmitter exocytosis might account for the cellular events involved in reinforcement of “cognitive reserve” in young and old animals.

Behavioral models of depression have theorized that access to positive reinforcement is a key component to the etiology and maintenance of depression. As a result, many treatments for depression such as Cognitive-Behavior Therapy, Acceptance and Commitment Therapy, and Behavioral Activation emphasize the importance of increased activity and creating an environment where rewards and reinforcement is available. Despite the theoretical underpinnings in depression and the success of these treatments incorporating the constructs, little is known about the relationship between the availability of environmental rewards and activation as it relates to depression. To address this gap in knowledge, a cross-sectional survey was administered to 409 undergraduate students at a medium-sized, Hispanic-Serving institute. Consistent with behavioral models of depression, the findings provided support for the contribution of an enriched environment as well as behavioral activation on depression. The findings indicate that the role of activation changes based on the level of environmental reward that is available. When taken together, the availability of environmental reward and activation accounted for a large amount of the variance of depression indicating support for behavioral models of depression.