Loneliness affects group-living mammals triggering a cascade of stress-dependent physiological disorders. Indeed, social isolation stress is a major risk factor for several neuropsychiatric disorders ...including anxiety and depression. Furthermore, social isolation has a negative impact on health and fitness. However, the neurobiological consequences of long-term chronic social isolation stress (LTCSIS) manifested during the adulthood of affected individuals are not fully understood. Our study assessed the impact of LTCSIS and social buffering (re-socialization) on the behavioural performance and social-affective brain-related proteins in diurnal, social, and long-lived Octodon degus (degus). Thereby, anxiety-like and social behaviour, and social recognition memory were assessed in male and female animals subjected to a variety of stress-inducing treatments applied from post-natal and post-weaning until their adulthood. Additionally, we evaluated the relationship among LTCSIS, Oxytocin levels (OXT), and OXT-Ca2+-signalling proteins in the hypothalamus, the hippocampus, and the prefrontal cortex. Our findings suggest that LTCSIS induces anxiety like-behaviour and impairs social novelty preference whereas sociability is unaffected. On the other hand, re-socialization can revert both isolation-induced anxiety and social memory impairment. However, OXT and its signalling remained reduced in the abovementioned brain areas, suggesting that the observed changes in OXT-Ca2+ pathway proteins were permanent in male and female degus. Based on these findings, we conclude degus experience social stress differently, suggesting the existence of sex-related mechanisms to cope with specific adaptive challenges.
Abstract
Water use practices and conservation are the result of complex sociotechnical interactions of political, economic, hydroclimatic, and social factors. While the drivers of water demand have ...been extensively studied, they have traditionally been applied to models that assume stationary relationships between these various factors, and usually do not account for potential societal changes in response to increased scarcity awareness. For example, following a period of sustained low demand such as during a drought, communities often increase water use during a hydrologically wet period, a phenomenon known as “rebounding” water use. Previous experiences show the extent of this rebound is not a straightforward function of policy and efficiency improvements, but may also reflect short‐term or long‐lasting change in community behavior, which are not easily captured by models that assume stationarity. In this work, we develop a system dynamics model to represent water demand as a function of both structural and social factors. We apply this model to the analysis of three diverse water utilities in the San Francisco Bay Area between 1980 and 2017, identifying drought response trends and drivers over time. Our model is consistent with empirical patterns and historical context of water use in California, and provides important insights on the rebound phenomenon that can be extended to other locations. This comparative assessment indicates that policies, public outreach, and better data availability have played a key role in raising public awareness of water scarcity, especially with the raise of the internet era in recent years.
Key Points
A system dynamics model is developed to examine social and structural factors of water conservation and the water use rebound phenomenon
We examine water conservation and rebound in the historical context of drought in California over the past four decades
Drought‐related political actions and public engagement are correlated to shifts in social memory and the prevalence of water conservation
•Chronic T. gondii infection in mice impairs sociability, social recognition memory.•Neuronal activation upon social interaction is impaired in relevant brain regions.•Functional connectivity in the ...brain is altered after chronic T. gondii infection.•Infection leads to a dysregulation of synaptic signalling proteins.
Toxoplasma gondii (T. gondii) is a neurotropic parasite that is associated with various neuropsychiatric disorders. Rodents infected with T. gondii display a plethora of behavioural alterations, and Toxoplasma infection in humans has been strongly associated with disorders such as schizophrenia, in which impaired social behaviour is an important feature. Elucidating changes at the cellular level relevant to neuropsychiatric conditions can lead to effective therapies. Here, we compare changes in behaviour during an acute and chronic T. gondii infection in female mice. Further, we notice that during chronic phase of infection, mice display impaired sociability when exposed to a novel conspecific. Also, we show that T. gondii infected mice display impaired short-term social recognition memory. However, object recognition memory remains intact. Using c-Fos as a marker of neuronal activity, we show that infection leads to an impairment in neuronal activation in the medial prefrontal cortex, hippocampus as well as the amygdala when mice are exposed to a social environment and a change in functional connectivity between these regions. We found changes in synaptic proteins that play a role in the process of neuronal activation such as synaptophysin, PSD-95 and changes in downstream substrates of cell activity such as cyclic AMP, phospho-CREB and BDNF. Our results point towards an imbalance in neuronal activity that can lead to a wider range of neuropsychiatric problems upon T. gondii infection.
Cerebral ischemia/reperfusion injury impairs learning and memory in patients. Studies have shown that synaptic function is involved in the formation and development of memory, and that DNA ...methylation plays a key role in the regulation of learning and memory. To investigate the role of DNA hypomethylation in cerebral ischemia/reperfusion injury, in this study, we established a rat model of cerebral ischemia/reperfusion injury by occlusion of the middle cerebral artery and then treated the rats with intraperitoneal 5-aza-2′-deoxycytidine, an inhibitor of DNA methylation. Our results showed that 5-aza-2′-deoxycytidine markedly improved the neurological function, and cognitive, social and spatial memory abilities, and dose-dependently increased the synaptic density and the expression of SYP and SHANK2 proteins in the hippocampus in a dose-dependent manner in rats with cerebral ischemia/reperfusion injury. The effects of 5-aza-2′-deoxycytidine were closely related to its reduction of genomic DNA methylation and DNA methylation at specific sites of the Syp and Shank2 genes in rats with cerebral ischemia/reperfusion injury. These findings suggest that inhibition of DNA methylation by 5-aza-2′-deoxycytidine promotes the recovery of learning and memory impairment in a rat model of cerebral ischemia/reperfusion injury. These results provide theoretical evidence for stroke treatment using epigenetic methods.
Acetylcholine (ACh), released in the hippocampus from fibers originating in the medial septum/diagonal band of Broca (MSDB) complex, is crucial for learning and memory. The CA2 region of the ...hippocampus has received increasing attention in the context of social memory. However, the contribution of ACh to this process remains unclear. Here, we show that in mice, ACh controls social memory. Specifically, MSDB cholinergic neurons inhibition impairs social novelty discrimination, meaning the propensity of a mouse to interact with a novel rather than a familiar conspecific. This effect is mimicked by a selective antagonist of nicotinic AChRs delivered in CA2. Ex vivo recordings from hippocampal slices provide insight into the underlying mechanism, as activation of nAChRs by nicotine increases the excitatory drive to CA2 principal cells via disinhibition. In line with this observation, optogenetic activation of cholinergic neurons in MSDB increases the firing of CA2 principal cells in vivo. These results point to nAChRs as essential players in social novelty discrimination by controlling inhibition in the CA2 region.
In the past thirty years, social memory of the Eurasian youth has been influenced by many actors of the commerative space, who often pursue their own goals in the struggle to legitimize the new ...political order and their policies of the radical economic transformation. The results of their efforts should be taken into account in the implementation of one of the most important joint projects of the post-Soviet countries - Eurasian integration, because social memory of the youth is the most important resource for its success. The study aims at clarifying and evaluating the mechanisms for preserving information about the past, the peculiarities of the generation Y ideas about the common history and the current stage of the EAEU construction, which are present in the public discourse, and at revealing the relationship between attitudes to the past and to the Eurasian integration, the influence of social memory on the personal worldview, the forms and methods of its reconstruction in the interests of the post-Soviet countries interaction and efficiency of the politics of memory. The formation of social memory is defined as the activity of actors (individuals, groups, organizations, social institutions, communities) aimed at the interpretation of the collective past and common present by the youth of the countries participating in the Eurasian integration. The empirical object of the study - young citizens of the member states and candidates for joining the EAEU (18-38 years old), who live, study or work in Moscow. The article considers the respondents assessments of the contribution of each of the actors to the social memory formation and describes social memory of the generation Y as a set of views, feelings and moods reflecting the perception of the Soviet past and the common present. The authors insist on the purposeful policy of the leaders of the countries, participating in the Eurasian integration, to ensure the reconstruction of the youths social memory and the consolidation of societies.
The article aims to present the social memory of revolutions occurring in Ukraine over the last three decades. The Revolution on Granite, the Orange Revolution, and the Revolution of Dignity ...constitute examples of young people’s revolutions, in which the students played a leading role in their initial stages. The research material was collected using the qualitative method. In-depth interviews conducted among respondents from different parts of Ukraine were used in the research. The research sample was purposely selected and consisted of 60 interviews. The results of the research indicate that Ukrainian society remembers the last two revolutions better. Knowledge of the Revolution on Granite is weaker. The first two revolutions are remembered as joyful events which inspired optimism for the future and promised positive changes. The Revolution of Dignity is a traumatic experience for the respondents, which is perceived through the prism of fear, anxiety, and dread. Disappointed hopes are also noticeable in the respondents’ statements. The respondents expected an improvement in living conditions and their economic situation, but it did not happen. Differences in the perceptions of protests among respondents from different parts of Ukraine were also observed. The respondents from Western and Central Ukraine recall the Maidans and their aftermath positively, while the respondents from Eastern Ukraine more often invoke negative memories of those events and their consequences.
Adolescence is a vulnerable period characterized by major cognitive changes. The mechanisms underlying the emergence of new cognitive functions are poorly understood. We find that a long-term ...depression of inhibitory transmission (iLTD) from parvalbumin-expressing (PV+) interneurons in the hippocampal area Cornu Ammonis 2 (CA2) is absent in young mice but emerges at the end of adolescence. We demonstrate that the maturation of both the perineuronal net (PNN) and signaling through ErbB4 is required for this plasticity. Furthermore, we demonstrate that social recognition memory displays the same age dependence as iLTD and is impaired by targeted degradation of the PNN or iLTD blockade in area CA2. Our data reveal an unusual developmental rule for plasticity at the PV+ interneuron transmission in area CA2 and indicate that this plasticity is involved in the emergence of higher cognitive function, such as social memory formation, in late adolescence.
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•Inhibitory plasticity from PV+ interneurons in area CA2 emerges at the end of adolescence•The control of GABA release by the PNN and ErbB4 matures at the end of adolescence•Signaling through the PNN via NRG1 and ErbB4 is required for iLTD induction•Preventing iLTD induction in CA2 in vivo impairs social memory formation
Dominguez et al. describe the mechanisms involved in the emergence of a form of long-term plasticity at inhibitory synapses from parvalbumin-expressing interneurons in mouse hippocampal area CA2. Maturation of this plasticity potentially underlies the emergence of social memory during late adolescence.
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