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The complexity experienced in early life can affect trait development of individuals, including sociability and fearfulness. The modern dairy calf's rearing environment often lacks environmental and social complexity. This study examined the effects of early-life, non-maternal adult contact and access to a physically complex environment on the responses of dairy heifers to several stressors, including restraint, social isolation, and novelty at 18 months of age. From the age of 2-13 weeks, 60 dairy heifers (Bos taurus) were reared according to one of three treatments applied to 20 calves each: (1) Hand-reared at pasture in groups of ten, with three unrelated dry cows (+S); (2) Hand-reared at pasture in groups of ten (-S); or (3) Hand-reared in sheds in groups of 10-12 as a commercial control (CC). At 13 weeks, all treatment groups were mixed and managed at pasture as a single herd. At 18 months, the responses of 50 heifers to restraint in a crush, social isolation and a novel object were observed (+S = 16, -S = 17, CC = 17). Treatment did not influence responses to restraint or social isolation, but influenced some indicators of fearfulness during exposure to a novel object. Six +S heifers interacted with the novel object compared to 0 -S and one CC, and CC heifers spent around 50% more time in vigilance than +S or -S heifers. Dairy heifers provided with early-life social enrichment in the form of non-maternal adult contact may have reduced fear of novelty. The implications for lifelong ability to adapt to novel situations, such as entry into the milking herd, should be assessed.

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Neuroscience heavily relies on animal welfare in laboratory rodents as it can significantly affect brain development, cognitive function and memory formation. Unfortunately, laboratory animals are often raised in artificial environments devoid of physical and social stimuli, potentially leading to biased outcomes in behavioural assays. To assess this effect, we examined the impact of social and physical cage enrichment on various forms of motor coordination. Our findings indicate that while enriched-housed animals did not exhibit faster learning in eyeblink conditioning, the peak timing of their conditioned responses was slightly, but significantly, improved. Additionally, enriched-housed animals outperformed animals that were housed in standard conditions in the accelerating rotarod and ErasmusLadder test. In contrast, we found no significant effect of enrichment on the balance beam and grip strength test. Overall, our data suggest that an enriched environment can improve motor performance and motor learning under challenging and/or novel circumstances, possibly reflecting an altered state of anxiety.

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RATIONALE: In previous animal model studies, it was shown that drug sensitization is dependent upon physical environmental conditions. However, the effects of social housing conditions on drug sensitization is much less known. OBJECTIVE: The aim of the present study was to investigate the effects of social conditions, through the size of housing groups, on ethanol stimulant effects and ethanol-induced behavioral sensitization in mice. MATERIALS AND METHODS: Male and female Swiss mice were housed in groups of different sizes (isolated mice, two mice per cage, four mice per cage and eight mice per cage) during a six-week period. A standard paradigm of ethanol-induced locomotor sensitization was then started with one daily injection of 2.5 g/kg ethanol for 8 consecutive days. RESULTS: The results show that social housing conditions affect the acute stimulant effects of ethanol. The highest stimulant effects were observed in socially isolated mice and then gradually decreased as the size of the group increased. Although the rate of ethanol sensitization did not differ between groups, the ultimate sensitized levels of ethanol-induced stimulant effects were significantly reduced in mice housed in groups of eight. CONCLUSIONS: These results are consistent with the idea that higher levels of acute and sensitized ethanol stimulant effects are observed in mice housed in stressful housing conditions, such as social isolation.

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BACKGROUND: Several preclinical studies have demonstrated that environmental enrichment (EE) during abstinence reduces drug seeking for psychostimulant and opioid drugs. Drug seeking is dependent on activity within the dorsomedial prefrontal cortex, and enrichment has been able to reduce drug seeking-associated increases in c-Fos in this region. In this study, we tested the hypothesis that EE during abstinence from oxycodone self-administration would reduce drug seeking and c-Fos immunoreactivity within the prefrontal cortex in a cell-type specific manner. METHODS: Male rats self-administered oxycodone in two-hours sessions for three weeks, then underwent an initial drug seeking test under extinction conditions after one week of forced abstinence. Following this test, rats received either EE or remained individually housed in their home cage, then a second drug seeking test, with tissue collection immediately afterward. RESULTS: Compared to rats in standard housing, environmentally enriched rats had lower oxycodone seeking. In the prelimbic and infralimbic prefrontal cortices, the number of c-Fos+ cells was reduced, and this reduction was predominantly in inhibitory cells neurons, as evidenced by a reduction in the proportion of c-Fos+ cells in GAD+, but not CamKII+ cells. There was also a robust positive relationship between the number of c-Fos+ cells and persistence of oxycodone seeking in both the PrL and IL. CONCLUSIONS: These findings further support the effectiveness of enriched environments to reduce reactivity to drug-associated stimuli and contexts and provide a potential mechanism by which this occurs.

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Growth of lambs in an artificial rearing system is key to the economic success of sheep-milking farms. Social enrichment in the form of quiet human contact has been shown to increase growth rates of lambs after weaning, perhaps by reducing stress and enhancing immune function. One hundred fourteen artificially reared dairy ewe lambs were assigned either to a Social condition receiving quiet human company in three 20-min segments per day, or a Control condition without quiet human contact. Feeding and housing conditions were otherwise identical. Starting weights for the Social (M = 6.29 kg; SD = 1.19 kg) and Control (M = 6.38 kg; SD = 0.93 kg) lambs were the same, as were their weights after 3 weeks (Mcontrol = 8.89 kg, SD = 2.55 kg, Msocial = 8.63 kg, SD = 2.16 kg). Mortality rates were significantly lower (p = 0.041) in the Social condition (0%) than Control (8%). Thus, social enrichment may be important for the wellbeing of lambs and for economic viability in lamb-rearing.

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Aging is a risk factor for the development of breast cancer. Foundational science studies have supported associations among neuroinflammation, breast cancer, and chemotherapy, but to date, these associations are based on studies using young adult rodents. The current study examined the neuroinflammatory effects of chemotherapy in aged, tumor-naïve and tumor-bearing mice with or without social enrichment. Mice received two intravenous injections of doxorubicin (A) and cyclophosphamide (C) at a two-week interval. Brain immune cells were enriched/assessed via flow cytometry, seven days following the second chemotherapy injection. Social enrichment enhanced peripheral immune cell trafficking in aged tumor-naive mice treated with AC. Group housed aged tumor bearing mice receiving AC had reduced percentage of IL-6+ monocytes and granulocytes relative to their singly housed counterparts. Notably, group housing aged experimental mice with young cage partners significantly reduced TNF + monocytes, tumor volume, and tumor mass. These data illustrate the importance of social enrichment in attenuating neuroinflammation and are the first to demonstrate that social support with young housing partners reduces tumor growth in aged mice.

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The exclusion of social play within an adolescent group interferes with learning and the acquisition of essential social behavior during development and can cause modulations in the social brain areas. However, despite the importance of social play in adolescence, an in-depth explanation of its physiological mechanisms is limited because of the lack of experimental animal models that embody social play exclusion in human society. To determine the mechanism of social play in adolescence, we identified differences in emotional behavior and brain activity in animal models of social play exclusion that mimicked human society. Emotional changes in the social play exclusion and non-exclusion groups were examined by tracking social play-related social interaction behavior, social play-related space preference, social play-related locomotor behavior, and anxiety-like behavior using a behavioral data analysis program. Differences in brain activity among groups were identified using immunohistochemical staining. During the social play exclusion model, the rats preferred the partition zone to the other areas in the test chamber. The exclusion group preferred the partition and the center zone over the non-exclusion group. When comparing before and after the social play exclusion, the exclusion group showed a decrease in mobility and an increase in anxiety-like behavior compared to the non-exclusion group. We found that c-Fos expression in the dentate gyrus (DG) of the exclusion group was lower than that in the non-exclusion group, whereas c-Fos expression in the lateral habenula (LHb) of the exclusion group was higher than that in the non-exclusion group. Taken together, in adolescence, exclusion from social play with peers can increase anxiety-like behavior in the exclusion group and change the neuronal activity of the DG and LHb, suggesting that exclusion from social play is linked to modifications in the DG and LHb, which are regions associated with mood regulation.

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Introduction: Early social isolation (ESI) disrupts neurodevelopmental processes, potentially leading to long-lasting emotional and cognitive changes in adulthood. Communal nesting (CN), i.e., the sharing of parental responsibilities between multiple individuals in a nest, creates a socially enriching environment known to impact social and anxiety-related behaviors. Methods: This study examines the effects of (i) the CN condition and of (ii) ESI during the 3rd week of life (i.e., pre-weaning ESI) on motor, cognitive, and emotional domains during adolescence and adulthood in male and female rats reared in the two different housing conditions, as well as (iii) the potential of CN to mitigate the impact of ESI on offspring. Results: We found that in a spontaneous locomotor activity test, females exhibited higher activity levels compared to males. In female groups, adolescents reared in standard housing (SH) condition spent less time in the center of the arena, suggestive of increased anxiety levels, while the CN condition increased the time spent in the center during adolescence, but not adulthood, independently from ESI. The prepulse inhibition (PPI) test showed a reduced PPI in ESI adolescent animals of both sexes and in adult males (but not in adult females), with CN restoring PPI in males, but not in adolescent females. Further, in the marble burying test SH-ESI adolescent males exhibited higher marble burying behavior than all other groups, suggestive of obsessive-compulsive traits. CN completely reversed this stress-induced effect. Interestingly, ESI and CN did not have a significant impact on burying behavior in adult animals of both sexes. Discussion: Overall, our findings (i) assess the effects of ESI on locomotion, sensorimotor gating, and compulsive-like behaviors, (ii) reveal distinct vulnerabilities of males and females within these domains, and (iii) show how early-life social enrichment may successfully counteract some of the behavioral alterations induced by early-life social stress in a sex-dependent manner. This study strengthens the notion that social experiences during early-life can shape emotional and cognitive outcomes in adulthood, and points to the importance of social enrichment interventions for mitigating the negative effects of early social stress on neurodevelopment.

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This study aimed to determine the effects of early-life physical and social enrichment on the ability of dairy heifers to integrate into a herd of mature cows. Fifty heifer calves were reared from the ages of 2-13 weeks in one of three treatments: (1) Hand-reared and group-housed in sheds (CC); (2) Hand-reared and group-housed at pasture (-S); or (3) Hand-reared and group-housed at pasture, with 3 non-familial dry cows per group (+S). At 23 months of age, these heifers were introduced in groups to small herds of cows (Cows) at pasture. Social interactions were recorded continuously for two 1-h periods. Feeding, ruminating and resting behaviours of all animals and walking, standing and lying behaviours of 36 heifers only (+S = 14, -S = 13, CC = 9) were recorded for 48 h after mixing. Heifers that were managed as calves according to the CC treatment delivered less agonistic behaviour to other heifers after mixing than those reared in the +S or -S treatments (p = 0.002 and p = 0.041, respectively). On Day 2, +S heifers and cows spent the lowest proportion of time feeding (p = 0.961), with -S heifers spending significantly more time feeding than cows (p = 0.046), while CC heifers spent more time feeding than both +S heifers and cows (p = 0.027 and p < 0.002, respectively). Increasing the complexity of the early-life environment, particularly socially, may aid heifers in integrating into groups of multiparous cows later in life and shape their lifelong social experiences with same-age conspecifics.

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Individuals with more complex jobs experience better cognitive function in old age and a lower risk of dementia, yet complexity has multiple dimensions. Drawing on the Social Networks in Alzheimer Disease study, we examine the association between occupational complexity and cognition in a sample of older adults (N = 355). A standard deviation (SD) increase in complex work with people is associated with a 9% to 12% reduction in the probability of mild cognitive impairment or dementia, a 0.14-0.19 SD increase in episodic memory, and a 0.18-0.25 SD increase in brain reserve, defined as the gap (residual) between global cognitive function and magnetic resonance imaging (MRI) indicators of brain atrophy. In contrast, complexity with data or things is rarely associated with cognitive outcomes. We discuss the clinical and methodological implications of these findings, including the need to complement data-centered activities (e.g., Sudoku puzzles) with person-centered interventions that increase social complexity.

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Epidemiological evidence indicates that stress and aversive psychological conditions can affect cancer progression, while well-being protects against it. Although a large set of studies have addressed the impact of stress on cancer, not much is known about the mechanisms that protect from cancer in healthy psychological conditions. C57BL/6J mouse pups were exposed to an environmental enrichment condition consisting of being raised until weaning by the biological lactating mother plus a non-lactating virgin female (LnL = Lactating and non-Lactating mothers). The Control group consisted of mice raised by a single lactating mother (L = Lactating). Four months after weaning, mice from LnL and L conditions were exposed to intramuscular injection of 3-methylcolantrene (3MCA), a potent tumorigenic drug, and onset and progression of 3MCA-induced fibrosarcomas were monitored over time. Pups from the LnL compared to the L group received more parental care and were more resilient to stressful events during the first week of life. In association, the onset of tumors in LnL adults was significantly delayed. At the molecular level, we observed increased levels of wild-type p53 protein in tumor samples of LnL compared to L adults and higher levels of its target p21 in healthy muscles of LnL mice compared to the L group, supporting the hypothesis of potential involvement of p53 in tumor development. Our study sustains the model that early life care protects against tumor susceptibility.

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BACKGROUND: Digital technologies such as virtual reality (VR), humanoid robots, and digital companion pets have the potential to provide social and emotional enrichment for people living in aged care. However, there is currently limited knowledge about how technologies are being used to provide enrichment, what benefits they provide, and what challenges arise when deploying these technologies in aged care settings. OBJECTIVE: This study aims to investigate how digital technologies are being used for social and emotional enrichment in the Australian aged care industry and identify the benefits and challenges of using technology for enrichment in aged care. METHODS: A web-based survey (N=20) was distributed among people working in the Australian aged care sector. The survey collected information about the types of technologies being deployed and their perceived value. The survey was followed by semistructured interviews (N=12) with aged care workers and technology developers to investigate their experiences of deploying technologies with older adults living in aged care. Survey data were analyzed using summary descriptive statistics and categorizing open-ended text responses. Interview data were analyzed using reflexive thematic analysis. RESULTS: The survey revealed that a range of commercial technologies, such as VR, tablet devices, and mobile phones, are being used in aged care to support social activities and provide entertainment. Respondents had differing views about the value of emerging technologies, such as VR, social robots, and robot pets, but were more united in their views about the value of videoconferencing. Interviews revealed 4 types of technology-mediated enrichment experiences: enhancing social engagement, virtually leaving the care home, reconnecting with personal interests, and providing entertainment and distraction. Our analysis identified 5 barriers: resource constraints, the need to select appropriate devices and apps, client challenges, limited staff and organizational support, and family resistance. CONCLUSIONS: This study demonstrates that technologies can be used in aged care to create personally meaningful enrichment experiences for aged care clients. To maximize the effectiveness of technology-mediated enrichment, we argue that a person-centered care approach is crucial. Although enrichment experiences can be created using available technologies, they must be carefully selected and co-deployed with aged care clients. However, significant changes may be required within organizations to allow caregivers to facilitate individual technology-based activities for enrichment.

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Natural wildlife habitats are regularly subjected to anthropogenic pressures for different purposes, which are heading the biodiversity towards drastic decline. Several endangered wild species are raised in captivity with the aim of re-introduction. In some instances, mixed herds' rearing approach in captivity is adopted for providing social enrichment to captive stocks; however, the impacts of species on each other are least documented. We tested our prediction that keeping mixed herds of captive wild sheep and antelopes provides adequate social enrichment to the captive stocks: if interspecific interactions are balanced. In the current study, we studied the interspecific competition between mixed herds of captive Punjab urial (Ovis vignei punjabiensis) and Indian gazelle (Gazella bennettii) at Manglot Wildlife Park, Nowshera District, Khyber Pakhtunkhwa Province, Pakistan. We documented the negative effects of behavioural interference by Punjab urial on the feeding behaviour of Indian gazelle. The outcome of the current study revealed that Punjab urial are highly intolerant towards Indian gazelle, with high interference during feeding. Out of the total aggressive events, 77% (N = 1259) of events ended up with win/loss, in which Punjab urial dominated the Indian gazelle 3.5 times. Moreover, lopsided dominance by Punjab urial resulted in increased intraspecific competition among Indian gazelle (p < 0.001). Current study divulged Indian gazelle to be the subordinate species, with less intake of food. Instead of providing social enrichment by heterospecifics, the Punjab urial is negatively affecting the Indian gazelle, therefore, the results of our study discourage the practice of admix captive breeding for wild sheep and antelopes.

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Breast cancer survivors receiving chemotherapy often report increased anxiety and depression. However, the mechanism underlying chemotherapy-induced changes in affect remains unknown. We hypothesized that chemotherapy increases cytokine production, in turn altering exploratory and depressive-like behavior. To test this hypothesis, female Balb/C mice received two injections, separated by two weeks, of vehicle (0.9% saline) or a chemotherapeutic cocktail [9 mg/kg doxorubicin (A) and 90 mg/kg cyclophosphamide (C)]. Peripheral and central cytokine concentrations were increased one and seven days, respectively, after AC. Because of the beneficial effects of social enrichment on several diseases with inflammatory components, we examined whether social enrichment could attenuate the increase in peripheral and central cytokine production following chemotherapy administration. Socially isolated mice receiving AC therapy demonstrated increased depressive-like and exploratory behaviors with a concurrent increase in hippocampal IL-6. Whereas, group housing attenuated AC-induced IL-6 and depressive-like behavior. Next, we sought to determine whether central oxytocin may contribute to the protective effects of social housing after AC administration. Intracerebroventricular administration of oxytocin to socially isolated mice recapitulated the protective effects of social enrichment; specifically, oxytocin ameliorated the AC-induced effects on IL-6 and depressive-like behavior. Furthermore, administration of an oxytocin antagonist to group housed mice recapitulated the responses of socially isolated mice; specifically, AC increased depressive-like behavior and central IL-6. These data suggest a possible neuroprotective role for oxytocin following chemotherapy, via modulation of IL-6. This study adds to the growing literature detailing the negative behavioral effects of chemotherapy and provides further evidence that social enrichment may be beneficial to health.

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Environmental enrichment (EE) is one experimental manipulation that induces changes in the brain. However, it is important to distinguish between physical and social components of enrichment. To this end we established four groups of rats reared in different enriched environments during the adolescent period. Our results indicate heightened social memory and increased spine density in dentate gyrus specifically in socially enriched animals. Physical enrichment increased spine density in CA1. Dopamine D2 receptor expression in hippocampus was decreased across all enrichment conditions. Altogether, our results demonstrate differing effects of physical and social enrichment, supporting an important role for environment in synaptogenesis, behavior, and dopaminergic signaling.

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Objective: The aim of this study was to explore the influence of short-term (2-week) exposure to social (SE) and/or physical enrichment (PE) on the anxiety-like behavior of ovariectomized (OVX) NIH Swiss mice. Method : One week after surgery, each OVX mouse was housed under one of 4 social conditions: (1) isolated, (2) accompanied by an intact female, (3) accompanied by an intact male, or (4) in a community of 10 OVX individuals. The animals in each of these environments were divided into 2 subgroups, consisting of the presence and absence of PE. Following a 2-week exposure to the respective conditions, each OVX mouse was subjected to either the light/dark exploration test (LDT) or the elevated plus maze (EPM) to examine anxiety-like behavior. Results: The LDT and EPM showed very similar patterns. Compared to an impoverished environment, PE elicited a significant anxiolytic effect for OVX mice housed alone or in companion of an intact female (F [1, 54] = 16.11, P = 0.001). By contrast, mice living in community but without PE displayed anxiogenic-like behavior, perhaps due to crowding, compared to the animals living in isolation (F [1, 36] = 5.64, P = 0.023). Conclusion: This study emphasized the importance of taking housing conditions into account during the screening of new anxiolytic agents and the critical role of OVX in the regulation of anxiety.

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Social factors have a dual influence on addictive disorders. While social defeat stress in rodents increases the response to drug reward, positive social conditions, such as pair housing, increase stress resilience. The objective of the present study was to confirm whether oxytocin (OT) mediates this social buffering. To this end, male mice were housed in pairs and administered the OT receptor antagonist atosiban prior to each stress episode or for ten days after the stress protocol. The response to cocaine was assessed using a conditioned place preference paradigm. Our results confirmed that OT activity mediates the protective effect of pair housing and highlights its therapeutic potential.

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In rodents, the hippocampal dentate gyrus gives rise to newly generated dentate granule cells (DGCs) throughout life. This process, named adult hippocampal neurogenesis (AHN), converges in the functional integration of mature DGCs into the trisynaptic hippocampal circuit. Environmental enrichment (EE) is one of the most potent positive regulators of AHN. This paradigm includes the combination of three major stimulatory components, namely increased physical activity, constant cognitive stimulation, and higher social interaction. In this regard, the pro-neurogenic effects of physical activity and cognitive stimulation have been widely addressed in adult rodents. However, the pro-neurogenic potential of the social aspect of EE has been less explored to date. Here we tackled this question by specifically focusing on the effects of a prolonged period of social enrichment (SE) in adult female C57BL6 mice. To this end, 7-week-old mice were housed in groups of 12 per cage for 8 weeks. These mice were compared with others housed under control housing (2-3 mice per cage) or EE (12 mice per cage plus running wheels and toys) conditions during the same period. We analyzed the number and morphology of Doublecortin-expressing (DCX+) cells. Moreover, using RGB retroviruses that allowed the labeling of three populations of newborn DGCs of different ages in the same mouse, we performed morphometric, immunohistochemical, and behavioral determinations. Both SE and EE increased the number and maturation of DCX+ cells, and caused an increase in dendritic maturation in certain populations of newborn DGCs. Moreover, both manipulations increased exploratory behavior in the Social Interaction test. Unexpectedly, our data revealed the potent neurogenesis-stimulating potential of SE in the absence of any further cognitive stimulation or increase in physical activity. Given that an increase in physical activity is strongly discouraged under certain circumstances, our findings may be relevant in the context of enhancing AHN via physical activity-independent mechanisms.

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Environmental enrichment is known to improve brain plasticity and protect synaptic function from negative insults. In the present study we used the exposure to social enrichment to ameliorate the negative effect observed in post weaning isolated male rats in which neurotrophic factors, neurogenesis, neuronal dendritic trees and spines were altered markedly in the hippocampus. After the 4 weeks of post-weaning social isolation followed by 4 weeks of reunion, different neuronal growth markers as well as neuronal morphology were evaluated using different experimental approaches. Social enrichment restored the reduction of BDNF, NGF and Arc gene expression in the whole hippocampus of social isolated rats. This effect was paralleled by an increase in density and morphology of dendritic spines, as well as in neuronal tree arborisation in granule cells of the dentate gyrus. These changes were associated with a marked increase in neuronal proliferation and neurogenesis in the same hippocampal subregion that were reduced by social isolation stress. These results further suggest that the exposure to social enrichment, by abolishing the negative effect of social isolation stress on hippocampal plasticity, may improve neuronal resilience with a beneficial effect on cognitive function.

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Oxytocin appears to link social interaction and cell aging in rats, especially in females.

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