Impact Of Environmental Enrichment Research Articles

The Impact of Environmental Enrichment on the Cortisol Level of Shelter Cats.

Enriching cats' living environment in shelters is crucial in reducing their stress. Easier access to resources allows cats to display natural behavior. This study aimed to assess whether cats staying in an enriched environment would be less stressed than cats staying in a standard environment. The first group consisted of cats living in an environment with fewer resources (standard environment)-103 cats. The second group consisted of cats living in an enriched environment-76 cats. The research material consisted of hair collected to determine the cortisol level. The results indicate that cats from a more enriched environment have almost half the level of cortisol in hair than cats from an environment with fewer resources (0.059 ng/mg vs. 0.101 ng/mg; p = 0.000001).

Environmental enrichment enhances ethanol preference over social reward in male swiss mice: Involvement of oxytocin-dopamine interactions

The impact of environmental enrichment (EE) on natural rewards, including social and appetitive rewards, was investigated in male Swiss mice. EE, known for providing animals with various stimuli, was assessed for its effects on conditioned place preference (CPP) associated with ethanol and social stimuli. We previously demonstrated that EE increased the levels of the prosocial neuropeptide oxytocin (OT) in the hypothalamus and enhanced ethanol rewarding effects via an oxytocinergic mechanism. This study also investigated the impact of EE on social dominance and motivation for rewards, measured OT-mediated phospholipase C (PLC) activity in striatal membranes, and assessed OT expression in the hypothalamus. The role of dopamine in motivating rewards was considered, along with the interaction between OT and D1 receptors (DR) in the nucleus accumbens (NAc). Results showed that EE mice exhibited a preference for ethanol reward over social reward, a pattern replicated by the OT analogue Carbetocin. EE mice demonstrated increased social dominance and reduced motivation for appetitive taste stimuli. Higher OT mRNA levels in the hypothalamus were followed by diminished OT receptor (OTR) signaling activity in the striatum of EE mice. Additionally, EE mice displayed elevated D1R expression, which was attenuated by the OTR antagonist (L-368-889). The findings underscore the reinforcing effect of EE on ethanol and social rewards through an oxytocinergic mechanism. Nonetheless, they suggest that mechanisms other than the prosocial effect of EE may contribute to the ethanol pro-rewarding effect of EE and Carbetocin. They also point towards an OT-dopamine interaction potentially underlying some of these effects.

Impact of environmental enrichment on growth, behavior, and welfare of weanling piglets from pre-weaning to 6 weeks of age

Impact of environmental enrichment on growth, behavior, and welfare of weanling piglets from pre-weaning to 6 weeks of age

Environmental enrichment improves hippocampus-dependent spatial learning in female C57BL/6 mice in novel IntelliCage sweet reward-based behavioral tests.

The IntelliCage is an automated home-cage system that allows researchers to investigate the spontaneous behavior and learning abilities of group-housed mice. The IntelliCage enables us to increase the standardization and reproducibility of behavioral outcomes by the omission of experimenter-mouse interactions. Although the IntelliCage provides a less stressful environment for animals, standard IntelliCage protocols use controlled water access as the motivational driver for learning. To overcome possible water restrictions in slow learners, we developed a series of novel protocols based on appetitive learning, in which mice had permanent access to plain water but were additionally rewarded with sweetened water upon solving the task. C57BL/6NCrl female mice were used to assess the efficacy of these sweet reward-based protocols in a series of learning tasks. Compared to control mice tested with standard protocols, mice motivated with a sweet reward did equal to or better in operant performance and place learning tasks. Learning of temporal rules was slower than that in controls. When faced with a combined temporal x spatial working memory task, sweet-rewarded mice learned little and chose plain water. In a second set of experiments, the impact of environmental enrichment on appetitive learning was tested. Mice kept under enriched environment (EE) or standard housing (SH) conditions prior to the IntelliCage experiments performed similarly in the sweet-rewarded place learning task. EE mice performed better in the hippocampus-dependent spatial working memory task. The improved performance of EE mice in the hippocampus-dependent spatial working memory task might be explained by the observed larger volume of their mossy fibers. Our results confirm that environmental enrichment increases complex spatial learning abilities and leads to long-lasting morphological changes in the hippocampus. Furthermore, simple standard IntelliCage protocols could easily be adapted to sweet rewards, which improve animal welfare by removing the possibility of water restriction. However, complex behavioral tasks motivated by sweet reward-based learning need further adjustments to reach the same efficacy as standard protocols.

Citizen Environmental Behavior From the Perspective of Psychological Distance Based on a Visual Analysis of Bibliometrics and Scientific Knowledge Mapping

Global warming and other climate issues seriously threaten global sustainable development. As citizen environmental behavior can have a positive impact on the environment, it is of great theoretical significance and practical reference value to study the impact of psychological distance theory on citizen environmental behavior. This study obtained 2,633 related studies from 1980 to 2020 from the Web of Science as research objects, and used CiteSpace, VOSviewer, Netdraw, and other software programs to perform a bibliometric analysis, which can show the complex relationship implied in the citation, intuitively grasp the development context and hot frontier in this field, and help scholars better study citizen environmental behavior. The results and conclusions are as follows. (1) The related research covered three periods: infancy, growth, and outbreak. (2) Chronologically, the relevant research evolved from building models to analyze the impact of environmental enrichment on human environmental behavior, to studying the motivation behind citizen environmental behavior, and finally to paying attention to sustainable development. (3) A cluster analysis of high-frequency keywords identified three research hotspots: “drivers of psychological distance of environmental change perception on citizen environmental behavior,” “impact of social distance on adolescents’ behavior,” and “construal level theory and citizen green behavior.” Based on these findings, possible future research directions were identified, including changing from a single theory to a combination of multiple theories to comprehensively study citizen environmental protection behavior; analyzing the motivation of citizen environmental behavior and summarizing the general motivation of environmental behavior according to its internal relationship; and determining how to narrow the global psychological distance, strengthen the awareness of the community of human destiny, and explore the establishment of an efficient global climate cooperation mechanism.

Influence of environmental enrichment on the rehabilitation of white-eyed parakeet (Psittacara leucophthalmus)

The use of sensory, physical, cognitive, and alimentary stimuli are varieties of environmental enrichment used to minimize stress caused by the monotonous captive environment. The objective of this study was to verify the impact of environmental enrichment in escape-related behavioral stereotypies. Thirty birds of the species Psittacara leucophthalmus were observed from March to September 2016, received at the Wild Animal Recovery and Screening Center of the São Paulo State University (UNESP), School of the Veterinary Medicine campus Araçatuba. The methodology used for the behavioral observations was the focal animal with observation through filming were made by 18 hours per bird for three consecutive days, while physical, cognitive, food, and sensory enrichment methods were applied, and the assessment was carried out before, during, and after the application of environmental enrichment. The data were analyzed by the Shapiro-Wilk test for normality and by the Friedman test, which showed no significant difference (p >0.05) before, during, and after environmental enrichment. Despite the statistical analyses, the perception of the bird’s welfare improving was visually clear.

Impact of environmental enrichment and social group size in the aggressiveness and foraging activity of Serrapinnus notomelas

Fish are widely used in scientific research, and many species are bred for ornamental purposes and human consumption. Despite the large number of fish kept in captivity, research on the welfare of these animals has only recently intensified. One commonly used method for improving fish welfare is environmental enrichment, and the issue of animal density is central to this debate. Both enrichment and variation in fish density may have different impacts on the welfare of fish, which will depend on the biology of each species. In this study, we verified if environmental enrichment reduced aggressiveness and increased foraging activity in Serrapinnus notomelas in captivity. S. notomelas is a Neotropical characin commonly used in the aquarium trade. It has also been reared in captivity for scientific research purposes. However, studies on the welfare of S. notomelas in captivity are still lacking. We measured the aggressiveness and foraging activity of fishes in aquariums with different levels of enrichment (enriched and highly enriched), in comparison to an enrichment-free aquarium. The same behavioral aspects were quantified in groups of six and 12 individuals since it is known that group size influences these characteristics in shoal fishes. We found no influence of environmental enrichment on the species’ aggressiveness. However, fish housed in highly enriched aquariums increased their foraging activity to levels similar to fish housed in enrichment-free aquariums. We also found no influence of group size on the aggressiveness of individuals. However, increased group size had a positive effect on foraging activity, therefore we suggest housing S. notomelas with a minimum of 12 individuals. Results reinforce the need for species-specific investigation regarding both enrichment and shoal size to improve the welfare of captive fishes. We also encourage future studies on the effects of different enrichment levels, because we found that the level of enrichment affected the welfare of S. notomelas.

Alpha-synuclein at the nexus of genes and environment: the impact of environmental enrichment and stress on brain health and disease.

Accumulation of alpha‐synuclein protein aggregates is the hallmark neuropathologic feature of synucleinopathies such as Parkinson’s disease. Rare point mutations and multiplications in SNCA, the gene encoding alpha‐synuclein, as well as other genetic alterations are linked to familial Parkinson’s disease cases with high penetrance and hence constitute major genetic risk factors for Parkinson’s disease. However, the preponderance of cases seems sporadic, most likely based on a complex interplay between genetic predispositions, aging processes and environmental influences. Deciphering the impact of these environmental factors and their interactions with the individual genetic background in humans is challenging and often requires large cohorts, complicated study designs, and longitudinal set‐ups. In contrast, rodent models offer an ideal system to study the influence of individual environmental aspects under controlled genetic background and standardized conditions. In this review, we highlight findings from studies examining effects of environmental enrichment mimicking stimulation of the brain by its physical and social surroundings as well as of environmental stressors on brain health in the context of Parkinson’s disease. We discuss possible internal molecular transducers of such environmental cues in Parkinson’s disease rodent models and emphasize their potential in developing novel avenues to much‐needed therapies for this still incurable disease. This article is part of the Special Issue “Synuclein”

The impact of environmental enrichment in an acute stroke unit on how and when patients undertake activities

Objectives: To explore the effect of environmental enrichment within an acute stroke unit on how and when patients undertake activities, and the amount of staff assistance provided, compared with a control environment (no enrichment). Design: This is a substudy of a controlled before–after observational study. Setting: The study was conducted in an Australian acute stroke unit. Participants: The study included stroke patients admitted to (1) control and (2) environmental enrichment period. Intervention: The control group received standard therapy and nursing care, which was delivered one-on-one in the participants’ bedroom or a communal gym. The enriched group received stimulating resources and communal areas for mealtimes, socializing and group activities. Furthermore, participants and families were encouraged to increase patient activity outside therapy hours. Main measures: Behavioral mapping was performed every 10 minutes between 7.30 a.m. and 7.30 p.m. on weekdays and weekends to estimate activity levels. We compared activity levels during specified time periods, nature of activities observed and amount of staff assistance provided during patient activities across both groups. Results: Higher activity levels in the enriched group (n = 30, mean age 76.7 ± 12.1) occurred during periods of scheduled communal activity (P < 0.001), weekday non-scheduled activity (P = 0.007) and weekends (P = 0.018) when compared to the control group (n = 30, mean age 76.0 ± 12.8), but no differences were observed on weekdays after 5 p.m. (P = 0.324). The enriched group spent more time on upper limb (P < 0.001), communal socializing (P < 0.001), listening (P = 0.007) and iPad activities (P = 0.002). No difference in total staff assistance during activities was observed (P = 0.055). Conclusion: Communal activities and environmental resources were important contributors to greater activity within the enriched acute stroke unit.

The impact of environmental enrichment on the murine inflammatory immune response.

Living in a mentally and physically stimulating environment has been suggested to have a beneficial effect on the immune response. This study investigates these effects, utilizing a 2-week program of environmental enrichment (EE) and 2 models of acute inflammation: zymosan-induced peritonitis (ZIP) and the cecal ligation and puncture (CLP) model of sepsis. Our results revealed that following exposure to EE, mice possessed a significantly higher circulating neutrophil to lymphocyte ratio compared with control animals. When subject to ZIP, EE animals exhibit enhanced neutrophil and macrophage influx into their peritoneal cavity. Corresponding results were found in CLP, where we observed an improved capacity for enriched animals to clear systemic microbial infection. Ex vivo investigation of leukocyte activity also revealed that macrophages from EE mice presented an enhanced phagocytic capacity. Supporting these findings, microarray analysis of EE animals revealed the increased expression of immunomodulatory genes associated with a heightened and immunoprotective status. Taken together, these results provide potentially novel mechanisms by which EE influences the development and dynamics of the immune response.

Impact of Environmental Enrichment on Perineuronal Nets in the Prefrontal Cortex following Early and Late Abstinence from Sucrose Self-Administration in Rats.

Perineuronal nets (PNNs) are aggregates of extracellular matrix that form structures surrounding a subset of GABAergic interneurons. The staining intensity of PNNs appears to be related to plasticity. Environmental enrichment (EE) influences plasticity during adulthood: EE decreases the rewarding effects of drugs of abuse and diminishes both drug- and sucrose-seeking behavior. We determined the impact of EE on PNN intensity in the medial prefrontal cortex (mPFC) in rats trained to self-administer sucrose. We examined the number and intensity of PNNs within the prelimbic (PL), infralimbic (IL), and orbitofrontal (OF) regions of the mPFC of adult Long-Evans rats that were trained for sucrose self-administration followed by acute or chronic EE during abstinence and a cue-induced reinstatement test. Rats exposed to EE prior to a cue-induced reinstatement of sucrose seeking had an increase in PNN staining compared with rats in standard housing. Conversely, naïve rats given 1 day of EE had a decrease in PNN intensity in the PL, no change in the IL, and an increase in the OF. Our findings demonstrate that EE increases PNN intensity in the mPFC after sucrose training, suggesting that training enhances the ability of EE to increase PNN intensity. We further demonstrate an interaction between time of abstinence, duration of EE exposure, and cue-induced reinstatement. Our results suggest that increased PNN intensity after EE may alter the excitatory/inhibitory balance of mPFC neurons such that rats are less responsive to a sucrose cue.

The impact of early postnatal environmental enrichment on maternal care and offspring behaviour following weaning

The early postnatal period is a sensitive period in rodents as behavioural systems are developing and maturing during this time. However, relatively little information is available about the impact of environmental enrichment on offspring behaviour if enrichment is implemented only during this period. Here, environmental enrichment was provided from postnatal day 1 until weaning. On post-natal day 9, maternal behaviour and nonmaternal behaviour of the dam was observed. Nursing time in the enriched group was reduced but dams showed more non-maternal appetitive behaviours. Offspring were exposed to either the open field or the elevated plus maze (EPM) after weaning. In the open field, rats from the enriched group approached the more aversive inner zone of the open field later than control rats. Offspring from the enriched group made fewer entries into the inner zone and spent less time in this part of the arena. Enrichment had no impact on behaviour in the EPM. The present study provides evidence that postnatal enrichment can interfere with maternal behaviour in rats and can possibly lead to increased anxiety in the offspring. The findings suggest that enrichment procedures can have potentially unintended effects, interfering with the development of emotional behaviours in rats.

The impact of environmental enrichment on the outcome variability and scientific validity of laboratory animal studies.

It has been widely accepted for some time that species-appropriate environmental enrichment is important for the welfare of research animals, but its impact on research data initially received little attention. This has now changed, as the use of enrichment as one element of routine husbandry has expanded. In addition to its use in the care of larger research animals, such as nonhuman primates, it is now being used to improve the environments of small research animals, such as rodents, which are used in significantly greater numbers and in a wide variety of studies. Concern has been expressed that enrichment negatively affects both experimental validity and reproducibility. However, when a concise definition of enrichment is used, with a sound understanding of the biology and behaviour of the animal as well as the research constraints, it becomes clear that the welfare of research animals can be enhanced through environmental enrichment without compromising their purpose. Indeed, it is shown that the converse is true: the provision of suitable enrichment enhances the well-being of the animal, thereby refining the animal model and improving the research data. Thus, the argument is made that both the validity and reproducibility of the research are enhanced when proper consideration is given to the research animal's living environment and the animal's opportunities to express species-typical behaviours.

Environmental Enrichment Increases the GFAP+ Stem Cell Pool and Reverses Hypoxia-Induced Cognitive Deficits in Juvenile Mice

Premature children born with very low birth weight (VLBW) can suffer chronic hypoxic injury as a consequence of abnormal lung development and cardiovascular abnormalities, often leading to grave neurological and behavioral consequences. Emerging evidence suggests that environmental enrichment improves outcome in animal models of adult brain injury and disease; however, little is known about the impact of environmental enrichment following developmental brain injury. Intriguingly, data on socio-demographic factors from longitudinal studies that examined a number of VLBW cohorts suggest that early environment has a substantial impact on neurological and behavioral outcomes. In the current study, we demonstrate that environmental enrichment significantly enhances behavioral and neurobiological recovery from perinatal hypoxic injury. Using a genetic fate-mapping model that allows us to trace the progeny of GFAP+ astroglial cells, we show that hypoxic injury increases the proportion of astroglial cells that attain a neuronal fate. In contrast, environmental enrichment increases the stem cell pool, both through increased stem cell proliferation and stem cell survival. In mice subjected to hypoxia and subsequent enrichment there is an additive effect of both conditions on hippocampal neurogenesis from astroglia, resulting in a robust increase in the number of neurons arising from GFAP+ cells by the time these mice reach full adulthood.

The impact of environmental enrichment on sex-specific neurochemical circuitries – Effects on brain-derived neurotrophic factor and the serotonergic system

Experimental evidence in mice indicates that environmental conditions affect females and males differently. However, in a recent study analyzing the heterozygous mutation of brain-derived neurotrophic factor (BDNF), both sexes presented a similar emotional phenotype, which became obvious only under impoverished, but not in enriched conditions suggesting an “enrichment-induced” rescue. To investigate the basis of this behavioral “rescue” effect, we analyzed neurochemical changes (BDNF expression, serotonergic changes, and corticosterone) in the hippocampus, frontal cortex and hypothalamus of animals housed under respective conditions.In male mice, enrichment induced an increase of BDNF expression in the hippocampus of both BDNF heterozygous (BDNF+/−) and wild-types. Notably, in enriched-reared BDNF+/− mice BDNF mRNA and protein increased to levels comparable to those of wild-types in impoverished environment. In the frontal cortex of males, only wild-types presented an enrichment-induced increase of BDNF mRNA, while no effect of environment could be detected in BDNF protein levels of the male hypothalamus. A further male-specific effect of “environment” is the significant reduction of hypothalamic 5-hydroxyindoleacetic acid in enriched-housed wild-types.In female mice, environmental enrichment did not affect BDNF expression in the hippocampus and hypothalamus. However, comparable to males, an enrichment-induced increase of BDNF mRNA was detected in the frontal cortex of wild-types only. In contrast to males, no influence of environment on serotonergic parameters was observed.Male and female corticosterone levels were neither affected by “genotype” nor by “environment”.In conclusion, we propose that the rescue of the emotional phenotype by environmental enrichment in BDNF+/− mice is directed by distinct mechanisms in males and females. Only in male BDNF+/− mice the rescue is related to an increase in hippocampal BDNF expression suggesting that enrichment triggers different neuronal systems in a gender-specific manner.

Impact of environmental enrichment on neurogenesis in the dentate gyrus during the early postnatal period

Accumulating evidence shows that environmental enrichment increases neurogenesis in the adult hippocampal dentate gyrus. The goal of the current study was to examine the effect of environmental enrichment on hippocampal neurogenesis during early life stages. We used as an animal model the guinea pig, a precocious rodent that is early independent from maternal care. Animals were assigned to either a standard (control) or an enriched environment a few days after birth (P5–P6). Between P14 and P17 animals received one daily bromodeoxyuridine (BrdU) injection, to label dividing cells, and were sacrificed either on P18, to evaluate cell proliferation or on P45, to evaluate cell survival and differentiation. In 18-day old enriched animals, there was a larger number of BrdU-positive cells compared to that found in controls. At P45, enriched animals had more surviving cells and more cells with a neuronal phenotype than controls. Unbiased stereology revealed that enriched animals had more granule cells (+37% at P18 and +31% at P45). Results show that environmental enrichment in the early postnatal period notably increases cell proliferation and survival, with a large increase in the number of neurons forming the granule cell layer. The impact of environmental enrichment in the early postnatal period emphasizes the relevance of extrinsic factors in the modulation of neurogenesis during critical time windows of hippocampal development.

Nurturing brain plasticity: impact of environmental enrichment

Environmental enrichment (EE) is known to profoundly affect the central nervous system (CNS) at the functional, anatomical and molecular level, both during the critical period and during adulthood. Recent studies focusing on the visual system have shown that these effects are associated with the recruitment of previously unsuspected neural plasticity processes. At early stages of brain development, EE triggers a marked acceleration in the maturation of the visual system, with maternal behaviour acting as a fundamental mediator of the enriched experience in both the foetus and the newborn. In adult brain, EE enhances plasticity in the cerebral cortex, allowing the recovery of visual functions in amblyopic animals. The molecular substrate of the effects of EE on brain plasticity is multi-factorial, with reduced intracerebral inhibition, enhanced neurotrophin expression and epigenetic changes at the level of chromatin structure. These findings shed new light on the potential of EE as a non-invasive strategy to ameliorate deficits in the development of the CNS and to treat neurological disorders.

Permanency of gait improvement induced by vestibular stimulation in the mutant mouse staggerer.

Among the several methods that have been used to investigate the impact of environmental enrichment, on the behavior of an animal, the use of behaviorally deficient mutant mice has been especially useful. The use of this model allows one to investigate functional recovery compared to a known baseline (the normal animal) without the trauma and imprecision associated with surgical intervention. The present study extends a previous investigation that demonstrated a significant improvement in certain measures of the gait of the cerebellar mutant mouse staggerer, as a result of daily vestibular, muscular and visual stimulation. The results of the present study concerned the durability of that observed improvement. No clear-cut conclusion as to the permanency of the stimulation's effects could be drawn, because results differed according to the measures used. When tested two months after the end of the stimulation period the mutants ran more slowly, with as many "errors" as unstimulated mutants, leading one to infer a deleterious effect of the stimulation. On the other hand, if one considers only the number of "errors" during the test, one may conclude that early stimulation has a permanent advantageous effect of increasing the staggerer's receptivity to further stimulation. Other measures lead to more ambiguous conclusions. Finally, it is argued that even though true improvement in the staggerer's gait can be inferred from these results, and that at least some aspects of that improvement seem to be long-lasting, the generality of the findings cannot validly be extended beyond the precise experimental conditions.