Immune cell composition varies by age, sex and exposure to social adversity in free-ranging Rhesus Macaques.

Increasing age is associated with dysregulated immune function and increased inflammation-patterns that are also observed in individuals exposed to chronic social adversity. Yet we still know little about how social adversity impacts the immune system and how it might promote age-related diseases. Here, we investigated how immune cell diversity varied with age, sex and social adversity (operationalized as low social status) in free-ranging rhesus macaques. We found age-related signatures of immunosenescence, including lower proportions of CD20 + B cells, CD20 + /CD3 + ratio, and CD4 + /CD8 + T cell ratio - all signs of diminished antibody production. Age was associated with higher proportions of CD3 + /CD8 + Cytotoxic T cells, CD16 + /CD3- Natural Killer cells, CD3 + /CD4 + /CD25 + and CD3 + /CD8 + /CD25 + T cells, and CD14 + /CD16 + /HLA-DR + intermediate monocytes, and lower levels of CD14 + /CD16-/HLA-DR + classical monocytes, indicating greater amounts of inflammation and immune dysregulation. We also found a sex-dependent effect of exposure to social adversity (i.e., low social status). High-status males, relative to females, had higher CD20 + /CD3 + ratios and CD16 + /CD3 Natural Killer cell proportions, and lower proportions of CD8 + Cytotoxic T cells. Further, low-status females had higher proportions of cytotoxic T cells than high-status females, while the opposite was observed in males. High-status males had higher CD20 + /CD3 + ratios than low-status males. Together, our study identifies the strong age and sex-dependent effects of social adversity on immune cell proportions in a human-relevant primate model. Thus, these results provide novel insights into the combined effects of demography and social adversity on immunity and their potential contribution to age-related diseases in humans and other animals.

Development and Initial Performance of the Hospital Mental Health Risk Screen.

BACKGROUND: Patients hospitalized after emergency care are at risk for later mental health problems such as depression, anxiety, and posttraumatic stress disorder symptoms. The American College of Surgeons Committee on Trauma standards for verification require Level I and II trauma centers to screen patients at high risk for mental health problems. This study aimed to develop and examine the performance of a novel mental health risk screen for hospitalized patients based on samples that reflect the diversity of the US population. STUDY DESIGN: We studied patients admitted after emergency care to 3 hospitals that serve ethnically, racially, and socioeconomically diverse populations. We assessed risk factors during hospitalization and mental health symptoms at follow-up. We conducted analyses to identify the most predictive risk factors, selected items to assess each risk, and determined the fewest items needed to predict mental health symptoms at follow-up. Analyses were conducted for the entire sample and within 5 ethnic and racial subgroups. RESULTS: Among 1,320 patients, 10 items accurately identified 75% of patients who later had elevated levels of mental health symptoms and 71% of those who did not. Screen performance was good to excellent within each of the ethnic and racial groups studied. CONCLUSIONS: The Hospital Mental Health Risk Screen accurately predicted mental health outcomes overall and within ethnic and racial subgroups. If performance is replicated in a new sample, the screen could be used to screen patients hospitalized after emergency care for mental health risk. Routine screening could increase health and mental health equity and foster preventive care research and implementation.

The biology of aging in a social world: Insights from free-ranging rhesus macaques.

Social adversity can increase the age-associated risk of disease and death, yet the biological mechanisms that link social adversities to aging remain poorly understood. Long-term naturalistic studies of nonhuman animals are crucial for integrating observations of social behavior throughout an individual's life with detailed anatomical, physiological, and molecular measurements. Here, we synthesize the body of research from one such naturalistic study system, Cayo Santiago, which is home to the world's longest continuously monitored free-ranging population of rhesus macaques (Macaca mulatta). We review recent studies of age-related variation in morphology, gene regulation, microbiome composition, and immune function. We also discuss ecological and social modifiers of age-markers in this population. In particular, we summarize how a major natural disaster, Hurricane Maria, affected rhesus macaque physiology and social structure and highlight the context-dependent and domain-specific nature of aging modifiers. Finally, we conclude by providing directions for future study, on Cayo Santiago and elsewhere, that will further our understanding of aging across different domains and how social adversity modifies aging processes.

Mental health symptoms are comparable in patients hospitalized with acute illness and patients hospitalized with injury.

BACKGROUND: High rates of mental health symptoms such as depression, anxiety, and posttraumatic stress disorder (PTSD) have been found in patients hospitalized with traumatic injuries, but little is known about these problems in patients hospitalized with acute illnesses. A similarly high prevalence of mental health problems in patients hospitalized with acute illness would have significant public health implications because acute illness and injury are both common, and mental health problems of depression, anxiety, and PTSD are highly debilitating. METHODS AND FINDINGS: In patients admitted after emergency care for Acute Illness (N = 656) or Injury (N = 661) to three hospitals across the United States, symptoms of depression, anxiety, and posttraumatic stress were compared acutely (Acute Stress Disorder) and two months post-admission (PTSD). Patients were ethnically/racially diverse and 54% female. No differences were found between the Acute Illness and Injury groups in levels of any symptoms acutely or two months post-admission. At two months post-admission, at least one symptom type was elevated for 37% of the Acute Illness group and 39% of the Injury group. Within racial/ethnic groups, PTSD symptoms were higher in Black patients with injuries than for Black patients with acute illness. A disproportionate number of Black patients had been assaulted. CONCLUSIONS: This study found comparable levels of mental health sequelae in patients hospitalized after emergency care for acute illness as in patients hospitalized after emergency care for injury. Findings of significantly higher symptoms and interpersonal violence injuries in Black patients with injury suggest that there may be important and actionable differences in mental health sequelae across ethnic/racial identities and/or mechanisms of injury or illness. Routine screening for mental health risk for all patients admitted after emergency care could foster preventive care and reduce ethnic/racial disparities in mental health responses to acute illness or injury.

Impact of COVID-19 on student perceived stress, life satisfaction, and psychological flexibility: examination of gender differences.

Objective: To identify stress management practices and examine the impact of the COVID-19 pandemic on well-being among male and female physician assistant (PA) students. Participants: Participants included 1,239 students from nine PA programs who matriculated pre-pandemic, acute pandemic, or post-acute pandemic. Methods: Measures included questions about stress management practices and validated instruments assessing perceived stress, life satisfaction, and psychological flexibility. Data were analyzed for differences based on year and gender. Results: Exercise (91.6%), yoga (54.6%), meditation (34.3%), and journaling (32.5%) were commonly reported stress reduction practices. Newly matriculated PA students adjusted to the COVID-19 pandemic differently based on gender. Pre-pandemic, men and women reported similar levels of perceived stress and psychological flexibility, but female students reported higher life satisfaction. Post-acute pandemic, however, female students reported higher perceived stress and lower psychological flexibility. Conclusions: Wellness resources may be strengthened by approaches that account for differences based on gender.

Development of a Brief Version of the Dissociative Symptoms Scale and the Reliability and Validity of DSS-B Scores in Diverse Clinical and Community Samples.

The Dissociative Symptoms Scale (DSS) was developed to assess moderately severe types of dissociation (depersonalization, derealization, gaps in awareness and memory, and dissociative reexperiencing) that would be relevant to a range of clinical populations, including those experiencing trauma-related dissociation. The current study used data from 10 ethnically and racially diverse clinical and community samples (N = 3,879) to develop a brief version of the DSS (DSS-B). Item information curves were examined to identify items with the most precision in measuring above average levels of the latent trait within each subscale. Analyses revealed that the DSS-B preserved the factor structure and content domains of the full scale, and its scores had strong reliability and validity that were comparable to those of scores on the full measure. DSS-B scores showed high levels of measurement invariance across ethnoracial groups. Results indicate that DSS-B scores are reliable and valid in the populations studied.

Scheduled Opioid Administration in Hospice Patients Before and After Targeted Caregiver Education.

Background: Hospice and palliative care have been shown to increase patient satisfaction and improve symptom control at the end of life. Opioid analgesics are typically given around the clock at the end of life to maintain symptom control and prevent the need for larger doses later. Many hospice patients have some degree of cognitive impairment, putting them at risk of being undertreated for pain. Methods: This was a retrospective, quasi-experimental study at a 766-bed community hospital with hospice and palliative care services. Adult patients admitted to inpatient hospice care with active orders for scheduled opioids for at least 12 hours with at least 1 dose administered were included. The primary intervention was the creation and dissemination of education to non-intensive care nursing staff. The primary outcome was the administration rate of scheduled opioid analgesics to hospice patients before and after targeted caregiver education. Secondary outcomes included the rate of use of 1-time or as-needed opioids, the rate of use-of-reversal agents, and the impact of COVID-19 infection status on administration rates of scheduled opioids. Results: A total of 75 patients were included in the final analysis. The rate of missed doses was 5% in the pre-implementation cohort and 4% in the post-implementation cohort (P = .21). The rate of delayed doses was 6% in the pre-implementation cohort and 6% in the post-implementation cohort (P = .97). Secondary outcomes were similar between the two groups with the exception of a higher rate of delayed doses in patients with confirmed COVID-19 as compared to those without COVID-19 (P = .047). Conclusion: The creation and dissemination of nursing education were not associated with a decrease in missed or delayed doses of scheduled opioids in hospice patients.

Urinary cytokine measurements do not reflect surgery-induced inflammation in rhesus macaques.

Measurement of the health and disease status of free-ranging primates is often limited by a lack of available biomarkers of immune activation and inflammation that can be applied noninvasively via the measurement of urine or fecal samples. Here, we evaluate the potential usefulness of noninvasive urinary measurements of a number of cytokines, chemokines, and other markers of inflammation and infection. We took advantage of surgery-associated inflammation in seven captive rhesus macaques, collecting urine samples before and after the medical interventions. We measured these urine samples for 33 different markers of inflammation and immune activation that are known to be responsive to inflammation and infection in rhesus macaque blood samples, via the Luminex platform. We also measured all samples for concentrations of the soluble urokinase plasminogen activator receptor (suPAR), which we had validated in a prior study as an effective biomarker of inflammation. Despite urine samples being collected in captivity under ideal conditions (clean, no contamination with feces or soil, frozen quickly), 13/33 biomarkers measured via Luminex were found at concentrations below detection limits in >50% of samples. Of the remaining 20 markers, only 2 showed significant increases in response to surgery-IL18 and MPO (myeloperoxidase). However, suPAR measurements of the same samples show a consistent marked increase in response to surgery that is absent from the patterns of IL18 and MPO measurement. Given that our samples were collected under conditions that are greatly preferable to those usually encountered in the field, urinary cytokine measurements via the Luminex platform seem overall unpromising for primate field studies.

Dental Bite-Sized Bits: A Module for Teaching Common Oral Health Conditions to Multidisciplinary Students.

The Surgeon General's report in the year 2000 highlighted the association between chronic diseases and oral health infections. Current healthcare education programs, regrettably, report only 1 to 3 h of oral health instruction within curricula. In the years 2020-2022, as part of their respective oral health curricula, 278 first-year physician assistant and 12 pre-clinical second-year pharmacy students were invited to participate in a voluntary survey examining the effectiveness of animated succinct, online video-based oral health units. Among all student responses for the post-use survey, respondents "strongly agreed" or "agreed" that learning objectives of the unit(s) were achieved after reviewing the videos. Of the participants, 97% "strongly agreed" or "agreed" that the videos helped them understand information of which they had no prior knowledge. Similarly, 98% "strongly agreed" or "agreed" the information was appropriate for their level of knowledge. Most students, 93%, "strongly agreed" or "agreed" the exercise was a valuable learning experience. Regarding the importance of future interprofessional collaboration pertaining to a mutual patient's oral health, 95% of participants "strongly agreed" or "agreed" that they would be likely to collaborate. This study demonstrates the importance of oral health as a critical area of focus in healthcare education. The study also confirms the hypothesis that Dental Bite-Sized Bits units deliver engaging, valuable oral health education for preclinical healthcare learners, incorporating interprofessional perspectives from the disciplines of dental, pharmacy, and physician assistant.

The biology of aging in a social world:insights from free-ranging rhesus macaques.

Social adversity can increase the age-associated risk of disease and death, yet the biological mechanisms that link social adversities to aging remain poorly understood. Long-term naturalistic studies of nonhuman animals are crucial for integrating observations of social behavior throughout an individual's life with detailed anatomical, physiological, and molecular measurements. Here, we synthesize the body of research from one such naturalistic study system, Cayo Santiago Island, which is home to the world's longest continuously monitored free-ranging population of rhesus macaques. We review recent studies of age-related variation in morphology, gene regulation, microbiome composition, and immune function. We also discuss ecological and social modifiers of age-markers in this population. In particular, we summarize how a major natural disaster, Hurricane Maria, affected rhesus macaque physiology and social structure and highlight the context-dependent and domain-specific nature of aging modifiers. Finally, we conclude by providing directions for future study, on Cayo Santiago and elsewhere, that will further our understanding of aging across different domains and how social adversity modifies aging processes.

Development and cross-validation of a veterans mental health risk factor screen.

BACKGROUND: VA primary care patients are routinely screened for current symptoms of PTSD, depression, and alcohol disorders, but many who screen positive do not engage in care. In addition to stigma about mental disorders and a high value on autonomy, some veterans may not seek care because of uncertainty about whether they need treatment to recover. A screen for mental health risk could provide an alternative motivation for patients to engage in care. METHOD: Data from samples of veterans and traumatic injury survivors were analyzed to identify mental health risk factors that are characteristics of individuals or stressors or of post-trauma, post-deployment, or post-military service resources, experiences, or responses. Twelve risk factors were strongly related to PTSD (r > .50): current PTSD, depression, dissociation, negative thinking, and emotional lability symptoms, life stress, relationship stress, social constraints, and deployment experiences of a difficult environment, concerns about life and family, perceived threat, and moral injury. Items assessing each of these risk factors were selected and their validity to prospectively predict PTSD and/or depression 6 months later was assessed in a new sample of 232 VA primary care patients. RESULTS: Twelve items assessing dissociation, emotional lability, life stress, and moral injury correctly classified 86% of those who later had elevated PTSD and/or depression symptoms (sensitivity) and 75% of those whose later symptoms were not elevated (specificity). Performance was also very good for 110 veterans who identified as members of ethnic/racial minorities. CONCLUSIONS: Mental health status was prospectively predicted in VA primary care patients with high accuracy using a screen that is brief, easy to administer, score, and interpret, and fits well into VA's integrated primary care. When care is readily accessible, appealing to veterans, and not perceived as stigmatizing, information about mental health risk may result in higher rates of engagement than information about current mental disorder status.

Peer-supported mobile mental health for veterans in primary care: A pilot study.

One in four veteran primary care patients suffers from a mental health condition; however, most do not receive any treatment for these problems. Mobile health (mHealth) can overcome barriers to care access, but poor patient engagement limits the effectiveness and implementation of these tools. Peers may facilitate patient engagement with mHealth. We designed a protocol for peers to support implementation of mobile mental health tools in primary care and tested the feasibility, acceptability, and clinical utility of this approach. Thirty-nine patients across two Veterans Affairs sites who screened positive for depression during a primary care visit and were not currently in mental health treatment were enrolled. Participants were scheduled for four phone sessions with a peer over 8 weeks and introduced to five mobile apps for a range of transdiagnostic mental health issues (stress, low mood, sleep problems, anger, and trauma). Pre/post phone interviews using quantitative and qualitative approaches assessed participants' self-reported app use, satisfaction with the intervention, symptom change (stress, anxiety, depression, insomnia), and progress with personal health goals. On average, patients reported using 3.04 apps (SD = 1.46). Per the Client Satisfaction Questionnaire, global satisfaction with the intervention was high (M = 25.71 out of 32, SD = 3.95). Pre to post participants reported significant improvements in their level of stress, based on a quantitative measure (p = .008), and 87% reported progress on at least one personal health goal. Findings support the feasibility, acceptability, and clinical utility of peer-supported mobile mental health for veterans in primary care. A randomized controlled trial of an adaptive version of this intervention is recommended. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Racial/ethnic differences in acute and longer-term posttraumatic symptoms following traumatic injury or illness.

BACKGROUND: Racial/ethnic differences in mental health outcomes after a traumatic event have been reported. Less is known about factors that explain these differences. We examined whether pre-, peri-, and post-trauma risk factors explained racial/ethnic differences in acute and longer-term posttraumatic stress disorder (PTSD), depression, and anxiety symptoms in patients hospitalized following traumatic injury or illness. METHODS: PTSD, depression, and anxiety symptoms were assessed during hospitalization and 2 and 6 months later among 1310 adult patients (6.95% Asian, 14.96% Latinx, 23.66% Black, 4.58% multiracial, and 49.85% White). Individual growth curve models examined racial/ethnic differences in PTSD, depression, and anxiety symptoms at each time point and in their rate of change over time, and whether pre-, peri-, and post-trauma risk factors explained these differences. RESULTS: Latinx, Black, and multiracial patients had higher acute PTSD symptoms than White patients, which remained higher 2 and 6 months post-hospitalization for Black and multiracial patients. PTSD symptoms were also found to improve faster among Latinx than White patients. Risk factors accounted for most racial/ethnic differences, although Latinx patients showed lower 6-month PTSD symptoms and Black patients lower acute and 2-month depression and anxiety symptoms after accounting for risk factors. Everyday discrimination, financial stress, past mental health problems, and social constraints were related to these differences. CONCLUSION: Racial/ethnic differences in risk factors explained most differences in acute and longer-term PTSD, depression, and anxiety symptoms. Understanding how these risk factors relate to posttraumatic symptoms could help reduce disparities by facilitating early identification of patients at risk for mental health problems.

Greater variability in rhesus macaque (Macaca mulatta) endocranial volume among males than females.

The greater male variability (GMV) hypothesis proposes that traits are more variable among males than females, and is supported by numerous empirical studies. Interestingly, GMV is also observed for human brain size and internal brain structure, a pattern which may have implications for sex-biased neurological and psychiatric conditions. A better understanding of neuroanatomical variability in non-human primates may illuminate whether certain species are appropriate models for these conditions. Here, we tested for sex differences in the variability of endocranial volume (ECV, a proxy for brain size) in a sample of 542 rhesus macaques (Macaca mulatta) from a large pedigreed free-ranging population. We also examined the components of phenotypic variance (additive genetic and residual variance) to tease apart the potential drivers of sex differences in variability. Our results suggest that males exhibit more variable ECVs, and that this pattern reflects either balancing/disruptive selection on male behaviour (associated with alternative male mating strategies) or sex chromosome effects (associated with mosaic patterns of X chromosome gene expression in females), rather than extended neurodevelopment among males. This represents evidence of GMV for brain size in a non-human primate species and highlights the potential of rhesus macaques as a model for sex-biased brain-based disorders.

The rhesus macaque as a success story of the Anthropocene.

Of all the non-human primate species studied by researchers, the rhesus macaque (Macaca mulatta) is likely the most widely used across biological disciplines. Rhesus macaques have thrived during the Anthropocene and now have the largest natural range of any non-human primate. They are highly social, exhibit marked genetic diversity, and display remarkable niche flexibility (which allows them to live in a range of habitats and survive on a variety of diets). These characteristics mean that rhesus macaques are well-suited for understanding the links between sociality, health and fitness, and also for investigating intra-specific variation, adaptation and other topics in evolutionary ecology.

Variation and heritability of retinal cone ratios in a free-ranging population of rhesus macaques.

A defining feature of catarrhine primates is uniform trichromacy-the ability to distinguish red (long; L), green (medium; M), and blue (short; S) wavelengths of light. Although the tuning of photoreceptors is conserved, the ratio of L:M cones in the retina is variable within and between species, with human cone ratios differing from other catarrhines. Yet, the sources and structure of variation in cone ratios are poorly understood, precluding a broader understanding of color vision variability. Here, we report a large-scale study of a pedigreed population of rhesus macaques (Macaca mulatta). We collected foveal RNA and analyzed opsin gene expression using cDNA and estimated additive genetic variance of cone ratios. The average L:M ratio and standard error was 1.03:1 ± 0.02. There was no age effect, and genetic contribution to variation was negligible. We found marginal sex effects with females having larger ratios than males. S cone ratios (0.143:1 ± 0.002) had significant genetic variance with a heritability estimate of 43% but did not differ between sexes or age groups. Our results contextualize the derived human condition of L-cone dominance and provide new information about the heritability of cone ratios and variation in primate color vision.

Wellness in Physician Assistant Education: Exploring Mindfulness, Well-Being, and Stress.

PURPOSE: The current study examined stress reduction activities most commonly used by matriculating physician assistant (PA) students to better understand how students are approaching self-care and management of stress. In particular, the study examined levels of mindfulness and well-being to understand how these relate to various stress reduction approaches at the time of matriculation. METHODS: Newly matriculated students at 9 PA programs located across the nation were surveyed (n = 294). Validated survey instruments assessed levels of mindfulness and general well-being. Stress reduction activities were also assessed. Univariate and multivariate analyses were used to examine levels of mindfulness and levels of well-being to see how these relate to various stress reduction approaches. RESULTS: The survey response rate was 72%. Nearly one-third of respondents (32%) identified meditation as one of their stress reduction activities, and more than half (53%) reported having participated in mindfulness practice at least once in the past year. Sixty-four percent of students reported awareness of mindfulness practices, while only 16% reported frequent practice within the year prior to matriculation. When looking at variables of interest, decentering and psychological flexibility were significant in accounting for student-reported perceived stress and life satisfaction. CONCLUSION: PA students are likely receptive to mindfulness-based interventions that have the potential to improve well-being and reduce stress. There is opportunity for programs to incorporate reliable and structured training within curricula that effectively increases levels of mindfulness and, in doing so, can lead to improvement in perceived stress and life satisfaction. Further research may assist educators in the development of strategies to promote student and clinician wellness.

Comparing the Effectiveness of Virtual and In-Person Delivery of Mindfulness-Based Skills Within Healthcare Curriculums.

Purpose: To promote well-being, healthcare education programs have incorporated mindfulness-based skills and principles into existing curriculums. Pandemic-related restrictions have compelled programs to deliver content virtually. Study objectives were to determine (1) whether teaching mindfulness-based skills within physician assistant (PA) programs can promote well-being and (2) whether delivery type (virtual vs. in-person) can impact the effectiveness. Methods: During this 2-year study, a brief mindfulness-based curriculum was delivered to incoming first-year students at six PA programs, while students at two programs served as controls. The curriculum was delivered in-person in year one and virtually in year two. Validated pre- and post-test survey items assessed mindfulness (decentering ability, present moment attention and awareness, and psychological flexibility) and well-being (perceived stress and life satisfaction). Results: As expected, coping abilities and well-being were adversely impacted by educational demands. The mindfulness-based curriculum intervention was effective in increasing mindfulness and life satisfaction, while decreasing perceived stress when delivered in-person. Virtual curricular delivery was effective in decreasing perceived stress but not improving life satisfaction. Over half of the participants receiving the curriculum reported positive changes on mindfulness measures with approximately 14-38% reporting a change of greater than one standard deviation. Changes on mindfulness measures explained 30-38% of the reported changes in perceived stress and 22-26% of the changes in life satisfaction. Therefore, the mindfulness curriculum demonstrated statistically significant improvements in measures of mindfulness and mitigated declines in life satisfaction and perceived stress. Conclusion: Mindfulness-based skills effectively taught in-person or virtually within PA programs successfully promote well-being.

Novel objects alter immediate early gene expression globally for ZENK and regionally for c-Fos in neophobic and non-neophobic house sparrows.

Neophobia - an animal's reluctance to approach novel objects, try new foods, or explore unfamiliar environments - affects whether animals can adapt to new environments and exploit novel resources. However, despite its importance, the neurobiological mechanisms underlying this personality trait are poorly understood. In this study, we examined regional brain activity using the expression of two immediate early genes (IEGs), ZENK and c-Fos, in response to novel objects or control conditions in captive house sparrows (Passer domesticus, n = 22). When exposed to novel objects, we predicted that we would see differential IEG activity in brain regions involved in regulating stress and emotion (hippocampus, medial ventral arcopallium, lateral septum), reward and learning (striatum), and executive function (NCL) between neophobic and non-neophobic individuals. To classify birds by phenotype, we used behavior trials that tested willingness to approach a food dish in the presence of several different novel objects, habituation to one novel object, and willingness to try several different novel foods. We then exposed birds to a new novel object or a control condition and assessed protein expression of two IEGs in neophobic vs non-neophobic individuals after this final exposure. An analysis of average sparrow feeding times in the presence of novel objects showed a bimodal distribution of neophobia behavior. There was also high repeatability of individual novel object responses, and average responses to all three trial types (novel object, novel food, and habituation to a novel object) were significantly correlated. Although we saw no differences between neophobic and non-neophobic birds in IEG expression in response to novel objects in any of the 6 brain regions examined, there was a significant global decrease in ZENK expression and a significant increase in c-Fos expression in the medial ventral arcopallium and the caudal hippocampus in response to novel objects compared to controls, suggesting that these two regions may be important in novelty detection and threat perception. Additionally, there was no object effect in the rostral hippocampus, which supports the hypothesis that the avian hippocampus may have a rostrocaudal functional gradient similar to the septotemporal gradient in mammals.

Aging and Senescence across Reproductive Traits and Survival in Superb Fairy-Wrens (Malurus cyaneus).

AbstractWhy do senescence rates of fitness-related traits often vary dramatically? By considering the full aging trajectories of multiple traits, we can better understand how a species' life history shapes the evolution of senescence within a population. Here, we examined age-related changes in sex-specific survival, reproduction, and several components of reproduction using a long-term study of a cooperatively breeding songbird, the superb fairy-wren (Malurus cyaneus). We compared aging patterns between traits by estimating standardized rates of maturation, age of onset of senescence, and rates of senescence while controlling for confounding factors reflecting individual variability in life history. We found striking differences in aging and senescence patterns between survival and reproduction as well as between reproductive traits. In both sexes, survival started to decline from maturity onward. In contrast, all reproductive traits showed improvements into early adulthood, and many showed little or no evidence of senescence. In females, despite senescence in clutch size, number of offspring surviving to independence did not decline in late life, possibly due to improvements in maternal care with age. Superb fairy-wrens have exceptionally high levels of extragroup paternity, and while male within-group reproductive success did not change with age, extragroup reproductive success showed a dramatic increase in early ages, followed by a senescent decline, suggesting that male reproductive aging is driven by sexual selection. We discuss how the superb fairy-wrens' complex life history may contribute to the disparate aging patterns across different traits.