A safety assessment of a 300-meter saturation dive at sea by mental ability and performance efficacy.

High pressure is an environmental characteristic of the deep sea that may exert critical effects on the physiology and mental abilities of divers. In this study we evaluated the performance efficacy and mental ability of four divers during a 300-meter helium-oxygen saturation dive at sea. Spatial memory, 2D/3D mental rotation functioning, grip strength, and hand-eye coordination ability were examined for four divers during the pre-dive, compression, decompression, and post-dive phases. The results showed that both the reaction time and the correct responses for the mental rotation and hand-eye coordination were slightly fluctuated. In addition, there was a significant decline in the grip strength of the left hand. It is concluded that the performance efficacy and mental ability of divers were virtually unaffected during 300-meter helium-oxygen saturation diving at sea.

Recovery of Chronic Stress-Triggered Changes of Hippocampal Glutamatergic Transmission.

Chronic stress results in neurochemical, physiological, immune, molecular, cellular, and structural changes in the brain and often dampens the cognition. The hippocampus has been one major focus in studying the stress responsivity and neural mechanisms underlying depression. Both acute and chronic stress stimuli lead to dynamic changes in excitatory transmission in the hippocampus. The present study examined the potential effects of spontaneous recovery after chronic stress on spatial memory function and glutamatergic transmission in the hippocampus. The results showed that chronic unpredicted mild stress transiently increased AMPA receptor GluA2/3 subunit expression, together with elevated PICK-1 protein expression. Spontaneous recovery restored the behavioral deficits in Barnes maze test, as well as the glutamate receptor expression changes. In conclusion, spontaneous recovery acts as an important mechanism in system homeostasis.

Chronic stress influences sexual motivation and causes damage to testicular cells in male rats.

INTRODUCTION: The suppressing effects of chronic stress on sexual desire have long been noted. Yet the biological mechanisms underlying such effects, especially at the level of cellular biology of testicular cells, have not been fully investigated. AIM: In the present study, we used a chronic unpredictable mild stress model to examine the association between chronic stress and structural alterations in the male reproductive system. MAIN OUTCOME MEASURES: The main outcome measures were the structural changes in sperm cells and Leydig cells of male rats. We used Agmo and Ellingsen's procedure to study partner preference behavior and observed the morphology of Leydig cells and germ cells in the control and stress groups. METHODS: Our methods included histology, electron microscopy, and animal behavior tests. RESULTS: The results showed that after 5 weeks of chronic stress exposure, partner preference behavior was impaired, the total surface area of Leydig cells and the number and diameter of seminiferous tubules decreased significantly, and the number and size of Leydig cells, as well as the number and the short-axis diameter of spermatogenic cells, also decreased. At the ultrastructural level, transmission electron microscopy revealed that the basement membranes of seminiferous tubules in stressed rats was far thinner, had a low density, and was uneven in thickness compared with the normal group, with enhanced apoptosis in germ cells. CONCLUSION: We conclude that chronic stress can trigger organic damage to testicular cells in male rats.

A possible change process of inflammatory cytokines in the prolonged chronic stress and its ultimate implications for health.

Sustained stress triggers series of changes in the brain and the body. At the early stage of stress, the activated hypothalamus-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS) axis can upregulate the levels of glucocorticoid (GCs) and catecholamines (CAs), respectively, and then they in turn inhibit the secretion of proinflammatory cytokines directly or indirectly while promoting the secretion of anti-inflammatory cytokines. At the prolonged stage, the sustained activated HPA demonstrates cortisol-resistance. At the same time, the inflammation related transcription pathway, such as nuclear-factor kappa-B (NF-κB) signaling, may be inhibited. Additionally, the inflammatory cytokines mediate a negative feedback regulation on themselves. Collectively, these regulations may increase the proinflammatory cytokines while decreasing the anti-inflammatory cytokines. This may further activate NF-κB and increase the proinflammation cytokines, which in turn reduce the inflammatory responses, contributing to various diseases.

Can Leading by Example Alone Improve Cooperation?

Cooperation is essential for the survival of human society. Understanding the nature of cooperation and its underlying mechanisms is crucial for studying human behavior. This paper investigates the impact of leadership on public cooperation by employing repeated sequential public goods games, as well as by examining whether leading by example (through rewards and punishments) can promote cooperation and organizational success. The leaders were assigned randomly and were given the authority to reward or punish. As a result, (1) the leaders showed a strong tendency toward reciprocity by punishing free riders and rewarding cooperators at their own expense, which enhanced the intrinsic motivation for others to follow their example; and (2) both rewards and punishments were effective in promoting cooperation, but punishment was more effective in sustaining a high level of collaboration. Additionally, leaders preferred using rewards and were more reluctant to use punishments. These findings are crucial for creating organizational structures that foster cooperation.

Hippocampal asymmetry: differences in structures and functions.

The structural asymmetry of bilateral hippocampus in mammals has been well recognized. Recent findings highlighted the accompanying functional asymmetries, as well as the molecular differences of the hippocampus. The present paper summarized these recent advances in understanding the hippocampal asymmetries at molecular, circuit and functional levels. Additionally, the addition of new neurons to the hippocampal circuit during adulthood is asymmetrical. We conclude that these differences in molecules and structures of bilateral hippocampus determined the variances in functionality between the two sides.

Evolutionary genomics analysis of human nucleus-encoded mitochondrial genes: implications for the roles of energy production and metabolic pathways in the pathogenesis and pathophysiology of demyelinating diseases.

The myelin sheath is a plasma membrane extension that lines nerve fibers to protect, support and insulate neurons. The myelination of axons in vertebrates enables fast, saltatory impulse propagation, and this process relies on organelles, especially on mitochondria to supply energy. Approximately 99% of mitochondrial proteins are encoded in the nucleus. Since mitochondria play a central role in the energy production and metabolic pathways, which are essential for myelinogenesis, studying these nucleus-encoded genes (nMGs) may provide new insights into the roles of energy metabolism in demyelinating diseases. In this work, a multiomics-based approach was employed to 1) construct a 1,740 human nMG subset with mitochondrial localization evidence obtained from the Integrated Mitochondrial Protein Index (IMPI) and MitoCarta databases, 2) conduct an evolutionary genomics analysis across mouse, rat, monkey, chimp, and human models, 3) examine dysmyelination phenotype-related genes (nMG subset genes with oligodendrocyte- ​and myelin-related ​phenotypes, OMP-nMGs) in MGI mouse lines and human patients, 4) determine the expression discrepancy of OMP-nMGs in brain tissues of cuprizone-treated mice, multiple sclerosis patients, and normal controls, and 5) conduct literature data mining to explore OMP-nMG-associated disease impacts. By contrasting OMP-nMGs with other genes, OMP-nMGs were found to be more ubiquitously expressed (59.1% vs. 16.1%), disease-associated (67.3% vs. 20.2%), and evolutionarily conserved within the human populations. Our multiomics-based analysis identified 110 OMP-nMGs implicated in energy production and lipid and glycan biosynthesis in the pathogenesis and pathophysiology of demyelinating disorders. Future targeted characterization of OMP-nMGs in abnormal myelination conditions may allow the discovery of novel nMG mediated mechanisms underlying myelinogenesis and related diseases.

Chronic Psychological Stress, but Not Chronic Pain Stress, Influences Sexual Motivation and Induces Testicular Autophagy in Male Rats.

Spermiogenesis is an important physiological process of mammalian fertilization. The germ cells are susceptible to the harmful effects of either psychological or physiological stress, which could induce male infertility. Our previous studies have found that chronic psychological stress could decrease sexual motivation. However, molecular mechanisms underlying male reproductive toxicity induced by chronic stress remain elusive. Recently, autophagy is proven to be involved in regulating the survival of germ cells, which is related to apoptosis. Herein, we established a chronic psychological stress model and a chronic pain model (physiological stressor) to explore the roles of autophagy in germ cells. Thirty-two male Sprague-Dawley rats were randomly divided into four groups, including the control group, the chronic psychological stress group, the SNI-sham group, and the chronic pain stress group. After exposure to stress for 35 days, open field test and the unconditioned sexual motivation test were performed. Following the behavioral experiment, autophagy in the rat testis was detected by Western blot and immunohistochemistry. We found both chronic psychological stress and chronic pain stress reduced total travel distance, the frequency of central crossing and increased the sensitivity to mechanical pain. While chronic psychological stress, but not the chronic pain stress declined sexual motivation. Chronic psychological stress prompt the expression of LC3-II with the decreased expression of p62, indicating that chronic psychological stress induced autophagy in rat testis. However, there was no significant difference between the expression of LC3-II and p62 in male rats under chronic pain stress. Therefore, chronic psychological stress and chronic pain stress have common behavior changes, but due to its unpredictability, chronic psychological stress leads to a decline in sexual motivation in male rats and induced the autophagy in testicular tissues.

Which is the ideal sanction for cooperation? An experimental study on different types of third-party sanctions.

Cooperation is the crux of many social problems, thus third-party sanction, as one of the most important ways to promote cooperation, is worth studying. The present study compared the effects of third-party punishment alone, third-party reward alone, and the combination of third-party reward and third-party punishment on cooperation in the context of a public goods experiment. In addition, we explored the characteristics of third-party sanctioning behaviors. A total of 280 students participated in the present study. The results showed that the operation of third-party sanctions did raise the level of cooperation and changed the discrete trend of cooperation-specifically, the differences between the cooperation level of every group member and the average level of the whole group. Furthermore, when third-party rewards and third-party punishments were used simultaneously in the public goods game (PGG), the level of cooperation was greatly enhanced, which meant that in the context of the third party, when punishment opportunities and reward opportunities coexist, they may have a "compensatory effect." In terms of the characteristics of sanctioning behaviors, the frequency of third-party sanctions did not differ significantly under different conditions (third-party punishment alone, third-party reward alone, and a combination of third-party reward and third-party punishment), and neither did expenditures on third-party sanctions, but the strategies that third parties used changed under different conditions, thus their effects on other group members' cooperative behavior varied under different conditions. The present study provides a comprehensive picture of how third parties behave in different conditions of third-party sanctions and how these sanctions exert influence on cooperation. Understanding these mechanisms can help us build more effective institutions.

The Integrative Effects of Leading by Example and Follower Traits in Public Goods Game: A Multilevel Study.

As an important way to understand leadership based on voluntary contribution mechanisms, the importance of leading by example to teamwork is becoming more and more evident in recent years. However, existing theories based on signaling and reciprocity perspectives, respectively, provide incomplete theoretical explaining. This study adds clarity by conducting a cross-level study that indicates a possible integrative framework of both signaling and reciprocity perspective on leading by example. Results were using data gathered from 130 Chinese college students, which were allocated into one baseline group and three experimental groups. A hierarchical model was used to examine the effects of leading by example on different levels. It is found that leading by example has positive effects on the cooperation of followers on both the group level and the individual level. Risk attitudes have positive effects on the cooperation of followers while trust attitudes have negative effects. Our findings suggest that both leading by example and personal traits significantly influence cooperation but on different levels. It also reminds us that a more systematic way to understand leadership is needed.

Chronic grouped social restriction triggers long-lasting immune system adaptations.

Chronic stress triggers rigorous psychological and physiological changes, including immunological system adaptations. However, the effects of long-term social restriction on human immune system have not been investigated. The present study is to investigate the effect of chronic stress on immune changes in human blood, with the stress stimuli controlled.10 male volunteers were group isolated from the modern society in a 50-meter-square room for 150 days, with enriched nutrition and good living conditions provided. Serum examination of immune system markers demonstrated numerous changes in different aspects of the immune functions. The changes were observed as early as 30 days and could last for another 150 days after the termination of the restriction period (300 days' time point). The results strongly argued for the adaptation of immunological system under chronic social restriction stress in adult human, preceding a clear change in psychological conditions. The changes of these immune system factors could as well act as the serum biomarkers in clinical early-diagnosis of stress-related disorders.

Transgenerational Inheritance of Paternal Neurobehavioral Phenotypes: Stress, Addiction, Ageing and Metabolism.

Epigenetic modulation is found to get involved in multiple neurobehavioral processes. It is believed that different types of environmental stimuli could alter the epigenome of the whole brain or related neural circuits, subsequently contributing to the long-lasting neural plasticity of certain behavioral phenotypes. While the maternal influence on the health of offsprings has been long recognized, recent findings highlight an alternative way for neurobehavioral phenotypes to be passed on to the next generation, i.e., through the male germ line. In this review, we focus specifically on the transgenerational modulation induced by environmental stress, drugs of abuse, and other physical or mental changes (e.g., ageing, metabolism, fear) in fathers, and recapitulate the underlying mechanisms potentially mediating the alterations in epigenome or gene expression of offsprings. Together, these findings suggest that the inheritance of phenotypic traits through male germ-line epigenome may represent the unique manner of adaptation during evolution. Hence, more attention should be paid to the paternal health, given its equivalently important role in affecting neurobehaviors of descendants.

The effects of stress on glutamatergic transmission in the brain.

Stress leads to detrimental effects on brain functions and results in various diseases. Recent studies highlight the involvement of glutamatergic transmission in pathogenesis of depressive behaviors and fears. Acute stress generates different impacts on the excitatory transmission compared to chronic stress. Different neuromodulators and epigenetic factors also participate in the alteration of synaptic transmission and the regulation of synaptic plasticity. Restoration of the glutamatergic transmission in stress-affected brain areas therefore provides novel directions of therapeutic interventions against stress.

Chronic stress impacts on olfactory system.

Chronic stress has detrimental effects on brain structures and functions. Previous studies mainly focused on prefrontal cortex and hippocampus, given their well-described roles in cognition and emotive processing. Chronic stress also leads to changes in other neural circuits, such as the olfactory system. Olfactory deficits were reported in both animal models and patients with depression. The present review summarizes the evidence linking chronic stress to neuropathology in the olfactory system, and analyzes the potential mechanistic insights underlying these changes. We propose also that olfactory system-targeting therapies could be beneficial to certain symptoms of patients suffering from stress-related neurological diseases.

Commentary: the effects of psychological stress on microglial cells in the brain.

Psychological stress leads to activation and proliferation of microglial cells in different brain regions. These effects are mediated by inflammatory cytokines, as well as stress hormones including glucocorticoids and norepinephrine. Eliminating microglia from the nervous system or blocking their activation prevented the stress-induced impairments on brain cognitive functions. We conclude that microglial cells are important meditators underlying anti-depression therapies.

Autophagy does not lead to the asymmetrical hippocampal injury in chronic stress.

Chronic stress results in hippocampal injury, and impairs learning and memory ability of animals. However the cellular mechanisms underlying cell death within hippocampus remain elusive. The present employed the rat model of chronic unpredicted mild stress (CUMS) and examined the cellular mechanism responsible for learning and memory impairments. The results showed that in correlation to the decreased ability in novelty cognition and reverse learning, CUMS led to loss of CA3 neurons in hippocampus, especially in the right hippocampus. Interestingly, autophagy contributed to the cell loss but was asymmetrical on both sides. This suggested that CUMS resulted in asymmetrical hippocampal injuries, which is not fully determined by autophagy.

Mental abilities and performance efficacy under a simulated 480-m helium-oxygen saturation diving.

Stress in extreme environment severely disrupts human physiology and mental abilities. The present study investigated the cognition and performance efficacy of four divers during a simulated 480 meters helium-oxygen saturation diving. We analyzed the spatial memory, 2D/3D mental rotation functioning, grip strength, and hand-eye coordination ability in four divers during the 0-480 m compression and decompression processes of the simulated diving. The results showed that except for its mild decrease on grip strength, the high atmosphere pressure condition significantly impaired the hand-eye coordination (especially above 300 m), the reaction time and correct rate of mental rotation, as well as the spatial memory (especially as 410 m), showing high individual variability. We conclude that the human cognition and performance efficacy are significantly affected during deep water saturation diving.

Changes of ultrastructure and downregulation of heat shock protein 70 and fibroblast growth factor 2 in gastric mucosa of rats with depressive-like behaviour.

OBJECTIVE: To understand the underlying mechanism of gastric symptoms in patients with depressive disorder. METHODS: This study tested in the rat depression model evoked with chronic mild stress whether the microstructure gastric mucosa is injured using scanning electronic microscopy and transmission electronic microscopy (TEM). In addition, the expression of heat shock protein 70 (HSP70) and fibroblast growth factor 2 (FGF2) proteins in the gastric mucosa were measured by Western blotting. RESULTS: We found that the gastric epithelial cells were ruptured and the gastric pits were widened in rats with depression. The amount of mucous granules was also reduced in the surface mucous cells. Moreover, parietal cells became active, and the secretory canaliculi were magnified. Expression of HSP70 and FGF2 was reduced in the gastric mucosa. CONCLUSIONS: These findings suggested that gastric symptoms in rats with depressive-like behaviour were caused by the injury of the gastric mucosa, AQ1 and HSP70 and FGF2 may be key molecules in the pathogenesis.