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In most mammals, new neurons are not only produced during embryogenesis but also after birth. Soon after adult neurogenesis was discovered, the influence of recruiting new neurons on cognitive functions, especially on memory, was documented. Likewise, the late process of neuronal production also contributes to affective functions, but this outcome was recognized with more difficulty. This review covers hypes and hopes of discovering the influence of newly-generated neurons on brain circuits devoted to affective functions. If the possibility of integrating new neurons into the adult brain is a commonly accepted faculty in the realm of mammals, the reluctance is strong when it comes to translating this concept to humans. Compiling data suggest now that new neurons are derived not only from stem cells, but also from a population of neuroblasts displaying a protracted maturation and ready to be engaged in adult brain circuits, under specific signals. Here, we discuss the significance of recruiting new neurons in the adult brain circuits, specifically in the context of affective outcomes. We also discuss the fact that adult neurogenesis could be the ultimate cellular process that integrates elements from both the internal and external environment to adjust brain functions. While we must be critical and beware of the unreal promises that Science could generate sometimes, it is important to continue exploring the potential of neural recruitment in adult primates. Reporting adult neurogenesis in humankind contributes to a new vision of humans as mammals whose brain continues to develop throughout life. This peculiar faculty could one day become the target of treatment for mental health, cognitive disorders, and elderly-associated diseases. The vision of an adult brain which never stops integrating new neurons is a real game changer for designing new therapeutic interventions to treat mental disorders associated with substantial morbidity, mortality, and social costs.

Latin America had no noncognitive skill activities promoted during the COVID-19 pandemic, affecting the development of educational competencies. Learning noncognitive skills is fundamental in civic education, as exemplified by Japan's Tokkatsu model, where daily practices, including facility cleaning, recycling, and voluntary assistance to teachers, form the foundation of a holistic education (both cognitive and noncognitive). This research investigated whether implementing Tokkatsu-related activities (cleaning, recycling, and volunteering) can foster noncognitive skill development in children within an online learning context for 5 months in a secondary public school in Peru. Factors influencing student motivation and participation were also identified, providing valuable insights for future initiatives. Utilizing a mixed-methods design, the study initially collected and analyzed quantitative data and then collected qualitative data through semistructured surveys and interviews with students and their families. Results showed that participating in the three abovementioned noncognitive skill activities promoted students' autonomy and empathy, developed students' leadership and decision-making skills, encouraged family commitment and cohesion among its members, and promoted the practice of learning by doing. These outcomes help improve students' motivation and cooperative behaviors. Therefore, integrating theory and practice through learning by doing aids in reshaping students' habits, with broader implications for future research and policy development. Amid the COVID-19 pandemic, students in Latin America did not receive any noncognitive skill activities, which are fundamental for their holistic development. Conversely, Japan promotes Tokkatsu, which encompasses the daily practice of noncognitive skill activities, such as cleaning, recycling, and volunteering. Tokkatsu may explain the disciplined nature of Japanese citizens, especially when it comes to cleanliness. In this pilot study, we developed and implemented a Tokkatsu-inspired project for 5 months in secondary level students from one of the public schools in Peru. We then evaluated its outcomes and the factors influencing student participation to this project. We observed that through participation in noncognitive skill activities, students developed autonomy, empathy, leadership skills, and decision-making skill, practiced \"learning by doing,\" established family commitment, and strengthened the relationship between the family and the school. Therefore, the integration of these Tokkatsu activities in the school curriculum is valuable, fostering a holistic development for children.

Olfaction is an important sensory modality driving fundamental behaviors. During odor-dependent learning, a positive value is commonly assigned to an odorant, and multiple forms of plasticity are involved when such odor–reward associations are formed. In rodents, one of the mechanisms underlying plasticity in the olfactory bulb consists in recruiting new neurons daily throughout life. However, it is still unknown whether adult-born neurons might participate in encoding odor value. Here, we demonstrate that exposure to reward-associated odors specifically increases activity of adult-born neurons but not preexisting neurons. Remarkably, adult-born neuron activation during rewarded odor presentation heightens discrimination learning and enhances the ability to update the odor value during reversal association. Moreover, in some cases, activation of this interneuron population can trigger olfactory learning without sensory stimulation. Taken together, our results show a specific involvement of adult-born neurons in facilitating odor–reward association during adaptive learning.

Using optogenetic activation of adult-born neurons in the mouse olfactory bulb, the authors find that selective stimulation of new interneurons generated during adulthood, but not earlier, accelerates learning in a two-odor discrimination task and improves olfactory memory. Thousand of local interneurons reach the olfactory bulb of adult rodents every day, but the functional effect of this process remains elusive. By selectively expressing channelrhodopsin in postnatal-born mouse neurons, we found that their activation accelerated difficult odor discrimination learning and improved memory. This amelioration was seen when photoactivation occurred simultaneously with odor presentation, but not when odor delivery lagged by 500 ms. In addition, learning was facilitated when light flashes were delivered at 40 Hz, but not at 10 Hz. Both in vitro and in vivo electrophysiological recordings of mitral cells revealed that 40-Hz stimuli produced enhanced GABAergic inhibition compared with 10-Hz stimulation. Facilitation of learning occurred specifically when photoactivated neurons were generated during adulthood. Taken together, our results demonstrate an immediate causal relationship between the activity of adult-born neurons and the function of the olfactory bulb circuit.

Bipolar disorders are defined by recurrences of depressive and manic episodes. The pathophysiology is still unknown, and translating clinical symptoms into behaviors explorable in animal models is challenging. Animal models of bipolar disorder do not exist because cyclicity of the disease is impossible to mimic, and it is therefore necessary to study mania and depression models separately. Beyond mood, emotional biases differentiate bipolar states in humans. Mania is associated with positive biases, e.g. emotional stimuli become more rewarding and less aversive, and the opposite for depression. We propose to assess behavioral hedonic responses to innately appetitive and aversive olfactory and gustatory cues in mice as proxies for the assigned emotional valence. A mania model is therefore supposed to exhibit positive hedonic bias. Using the GBR 12909 mania model, we observed the classical hyperactivity phenotype, along with low depressive-like but high anxiety-like behaviors. Unexpectedly, GBR 12909-treated mice exhibited strong negative hedonic biases. Consequently, the GBR 12909 model of mania might not be appropriate for studying emotional disturbances associated with mania states. We propose olfactory and gustatory preference tests as crucial assessment for positive and negative valence biases, necessary for precisely characterizing animal models of bipolar disorders.

Background Chronic non-communicable diseases entail high impact on health systems in Brazil and worldwide. Among the most frequent are the musculoskeletal conditions which comprise a group of diseases that influence individuals’ physical status, quality of life and functional capacity. Epidemiological studies investigating the scale of such conditions in the adult population are scarce in Brazil. This study estimates the prevalence of chronic musculoskeletal conditions and their association with demographic, socioeconomic, behavioural and clinical factors. Methods Cross-sectional study with data from Brazil’s 2013 National Health Survey ( Pesquisa Nacional de Saúde ), a nationwide household survey of 60,202 adults. Musculoskeletal conditions were specified by self-reported medical diagnosis of arthritis or rheumatism and self-reported spinal disorders. The variables were examined using a hierarchical model of determination. Prevalences of musculoskeletal conditions were calculated with their respective 95% confidence intervals for Brazil and its five regions. Prevalence ratios (PRs) were obtained by Poisson regression with robust variance. Results Of the 60,202 individuals evaluated, 21.6% presented musculoskeletal conditions, with higher prevalences for females, older adults, indigenous, those living with a partner, low education, no occupational activity, those living in the South Region of Brazil, in rural areas, daily smokers, sedentary, obese, those who did not drink alcohol, with depressive symptoms or suffering from three or more chronic diseases. Multivariate analysis identified strong associations with advanced age (PR = 3.61; 95% CI 3.27-3.98), depressive symptoms (PR = 1.69; 95% CI 1.57-1.81) and multimorbidity (PR = 1.94; 95% CI 1.77-2.12). Conclusions The results show high prevalence of musculoskeletal conditions in Brazil’s adult population. Considering the process of aging and steady growth in chronic diseases, this study underlines the need for health policies directed to prevention, treatment and rehabilitation for people affected by chronic musculoskeletal conditions.

This study aims to provide a technique applied to archaeology to estimate lidar-based aboveground biomass (AGB) in contemporary tropical forests surrounding archaeological sites. Accurate AGB estimations are important to serve as a baseline to evaluate the wood resources that the ancient Maya could have used for the development of their cities. A lidar processing model is proposed to study the contemporary forest surrounding the Yaxnohcah archaeological site. As tropical forests are highly diverse environments where species are not uniformly distributed, it was necessary to consider the variation within the forest to obtain accurate AGB. Four vegetation communities were defined from a supervised classification of a Sentinel-2 satellite image. A stratified sample was then selected for the field survey that comprised 73 transects of 500 m2 each. To estimate the transect AGB, we used an allometric equation that requires diameter, height, and wood density measurements for identified species. Linear-derived models provided the relationship between field data with lidar statistics for each vegetation type. Predicted average AGB values agreed with those obtained in the field. However, they significantly differed between vegetation types, averaging 83 Mg/ha for lowland forest, 178 for transition forest, and 215 for upland forest communities. From those results, we created a map with wall-to-wall AGB estimates following the distribution of vegetation classes that could complement archaeological research of past land use. Vegetation classification also helped determine that there is a spatial relationship between vegetation communities and the distribution of archaeological settlement features for the ancient city of Yaxnohcah.

Pest control is a main concern in agriculture. Indiscriminate application of synthetic pesticides has caused negative impacts leading to the rapid development of resistance in arthropod pests. Plant secondary metabolites have been proposed as a safer alternative to conventional pesticides. Monoterpenoids have reported bioactivities against important pests; however, due to their high volatility, low water solubility and chemical instability, the application of these compounds has been limited. Nanosystems represent a potential vehicle for the broad application of monoterpenoids. In this study, an 1,8-cineole nanoemulsion was prepared by the low energy method of phase inversion, characterization of droplet size distribution and polydispersity index (PDI) was carried out by dynamic light scattering and stability was evaluated by centrifugation and Turbiscan analysis. Fumigant bioactivity was evaluated against Tetranychus urticae, Rhopalosiphum maidis and Bemisia tabaci. A nanoemulsion with oil:surfactant:water ratio of 0.5:1:8.5 had a droplet size of 14.7 nm and PDI of 0.178. Formulation was stable after centrifugation and the Turbiscan analysis showed no particle migration and a delta backscattering of ±1%. Nanoemulsion exhibited around 50% more bioactivity as a fumigant on arthropods when compared to free monoterpenoid. These results suggest that nanoformulations can provide volatile compounds of protection against volatilization, improving their bioactivity.

In general, mercury (Hg) undergoes biomagnification in aquatic systems. The absence of Hg biomagnification in a certain aquatic environment constitutes an exceptional finding and this seems to be the case for Sepetiba Bay, in Rio de Janeiro state (RJ), Brazil. There are three distinct ecological populations of Guiana dolphins in the Sepetiba Bay (SB)–Ilha Grande Bay (IGB) Complex, inhabiting: (1) the inner part of SB; (2) SB entrance; and (3) IGB. In addition, there are two other delphinid species, rough-toothed dolphin and Atlantic spotted dolphin, that feed on the SB–IGB Complex. Considering the widely employed use of cetaceans as sentinels of environmental contamination by bioaccumulative toxicants, we have biopsy sampled individuals of the abovementioned ecological populations/species for measuring skin Hg concentrations. Two Bryde’s whales and one humpback whale were biopsied in the SB–IGB Complex as well. Skin Hg concentrations [μg g−1 dry weight (dw)] of Guiana dolphins were the highest in IGB, followed by SB entrance and the inner part of SB (0.99–5.47; 0.09–6.00; 0.08–2.22). Considering all species investigated in the present study, skin Hg concentrations were found in the following order: humpback whale < Bryde's whale < Guiana dolphins from SB inner part < Guiana dolphins from SB entrance < Guiana dolphins IGB = Atlantic spotted dolphins < rough-toothed dolphins. The skin Hg concentrations found in Guiana dolphins from the inner part of Sepetiba Bay (0.08–2.22) and rough-toothed dolphins from the SB–IGB Complex (1.26–20.0) are among the lowest and highest ever reported for dolphins worldwide, respectively.