Sara B. Johnson

Adolescent Maturity and the Brain: The Promise and Pitfalls of Neuroscience Research in Adolescent Health Policy

Longitudinal neuroimaging studies demonstrate that the adolescent brain continues to mature well into the 20s. This has prompted intense interest in linking neuromaturation to maturity of judgment. Public policy is struggling to keep up with burgeoning interest in cognitive neuroscience and neuroimaging. However, empirical evidence linking neurodevelopmental processes and adolescent real-world behavior remains sparse. Nonetheless, adolescent brain development research is already shaping public policy debates about when individuals should be considered mature for policy purposes. With this in mind, in this article we summarize what is known about adolescent brain development and what remains unknown, as well as what neuroscience can and cannot tell us about the adolescent brain and behavior. We suggest that a conceptual framework that situates brain science in the broader context of adolescent developmental research would help to facilitate research-to-policy translation. Furthermore, although contemporary discussions of adolescent maturity and the brain often use a deficit-based approach, there is enormous opportunity for brain science to illuminate the great strengths and potentialities of the adolescent brain. So, too, can this information inform policies that promote adolescent health and well-being.

The Science of Early Life Toxic Stress for Pediatric Practice and Advocacy

Young children who experience toxic stress are at high risk for a number of health outcomes in adulthood, including cardiovascular disease, cancers, asthma, and depression. The American Academy of Pediatrics has recently called on pediatricians, informed by research from molecular biology, genomics, immunology, and neuroscience, to become leaders in science-based strategies to build strong foundations for children’s life-long health. In this report, we provide an overview of the science of toxic stress. We summarize the development of the neuroendocrine-immune network, how its function is altered by early life adversity, and how these alterations then increase vulnerability to disease. The fact that early environments shape and calibrate the functioning of biological systems very early in life is both a cautionary tale about overlooking critical periods in development and reason for optimism about the promise of intervention. Even in the most extreme cases of adversity, well-timed changes to children’s environments can improve outcomes. Pediatricians are in a unique position to contribute to the public discourse on health and social welfare by explaining how factors that seem distal to child health may be the key to some of the most intractable public health problems of our generation. We consider the challenges and opportunities for preventing toxic stress in the context of contemporary pediatric practice.

State of the art review: poverty and the developing brain

In the United States, >40% of children are either poor or near-poor. As a group, children in poverty are more likely to experience worse health and more developmental delay, lower achievement, and more behavioral and emotional problems than their more advantaged peers; however, there is broad variability in outcomes among children exposed to similar conditions. Building on a robust literature from animal models showing that environmental deprivation or enrichment shapes the brain, there has been increasing interest in understanding how the experience of poverty may shape the brain in humans. In this review, we summarize research on the relationship between socioeconomic status and brain development, focusing on studies published in the last 5 years. Drawing on a conceptual framework informed by animal models, we highlight neural plasticity, epigenetics, material deprivation (eg, cognitive stimulation, nutrient deficiencies), stress (eg, negative parenting behaviors), and environmental toxins as factors that may shape the developing brain. We then summarize the existing evidence for the relationship between child poverty and brain structure and function, focusing on brain areas that support memory, emotion regulation, and higher-order cognitive functioning (ie, hippocampus, amygdala, prefrontal cortex) and regions that support language and literacy (ie, cortical areas of the left hemisphere). We then consider some limitations of the current literature and discuss the implications of neuroscience concepts and methods for interventions in the pediatric medical home.

School-based mindfulness instruction for urban male youth: A small randomized controlled trial

OBJECTIVES Mindfulness-based stress reduction (MBSR) has been shown to improve mental health and reduce stress in a variety of adult populations. Here, we explore the effects of a school-based MBSR program for young urban males. PARTICIPANTS AND METHODS In fall 2009, 7th and 8th graders at a small school for low-income urban boys were randomly assigned to 12-session programs of MBSR or health education (Healthy Topics-HT). Data were collected at baseline, post-program, and three-month follow-up on psychological functioning; sleep; and salivary cortisol, a physiologic measure of stress. RESULTS Forty-one (22 MBSR and 19 HT) of the 42 eligible boys participated, of whom 95% were African American, with a mean age of 12.5 years. Following the programs, MBSR boys had less anxiety (p=0.01), less rumination (p=0.02), and showed a trend for less negative coping (p=0.06) than HT boys. Comparing baseline with post-program, cortisol levels increased during the academic terms for HT participants at a trend level (p=0.07) but remained constant for MBSR participants (p=0.33). CONCLUSIONS In this study, MBSR participants showed less anxiety, improved coping, and a possible attenuation of cortisol response to academic stress, when compared with HT participants. These results suggest that MBSR improves psychological functioning among urban male youth.

A New Framework for Childhood Health Promotion: The Role of Policies and Programs in Building Capacity and Foundations of Early Childhood Health

Although the connection between early life experiences and later health is becoming increasingly clear, what is needed, now, is a new organizing framework for childhood health promotion, grounded in the latest science. We review the evidence base to identify the steps in the overall pathway to ensuring better health for all children. A key factor in optimizing health in early childhood is building capacities of parents and communities. Although often overlooked, capacities are integral to building the foundations of lifelong health in early childhood. We outline a framework for policymakers and practitioners to guide future decision-making and investments in early childhood health promotion.

Incorporating Salivary Biomarkers Into Nursing Research: An Overview and Review of Best Practices

Analytes and biomarkers present in saliva may provide insight into individual differences in environmental chemical exposures, variation in reproductive hormones, therapeutic and illegal substance use, changes in stress-related physiology, and the immunologic footprints of infectious disease. The wealth of information provided by salivary analytes has the potential to enrich biobehavioral nursing research by enabling researchers to measure these individual differences in the clinic as well as in patients’ and participants’ everyday social worlds. In this article, the authors provide a roadmap for researchers new to this area who would like to learn more about integrating salivary biospecimens into the next generation of health research. In addition, the authors highlight best practices and strategies to avoid common pitfalls for researchers already engaged in this field.

Nonlinear Growth Kinetics of Breast Cancer Stem Cells: Implications for Cancer Stem Cell Targeted Therapy

Cancer stem cells (CSCs) have been identified in primary breast cancer tissues and cell lines. The CSC population varies widely among cancerous tissues and cell lines, and is often associated with aggressive breast cancers. Despite of intensive research, how the CSC population is regulated within a tumor is still not well understood so far. In this paper, we present a mathematical model to explore the growth kinetics of CSC population both in vitro and in vivo. Our mathematical models and supporting experiments suggest that there exist non-linear growth kinetics of CSCs and negative feedback mechanisms to control the balance between the population of CSCs and that of non-stem cancer cells. The model predictions can help us explain a few long-standing questions in the field of cancer stem cell research, and can be potentially used to predict the efficicacy of anti-cancer therapy.

Retaliatory Attitudes and Violent Behaviors Among Assault-Injured Youth

OBJECTIVES To examine the effect of retaliatory attitudes on subsequent violent behavior and fight-related injuries among youth who presented to the emergency department with assault injuries. DESIGN Assault-injured youth were interviewed at baseline, 6 months, and 18 months to assess fighting behavior, retaliatory attitudes, weapon carrying, and injury history as part of a larger randomized control trial. SETTING Two emergency departments in urban areas were selected for the study. PARTICIPANTS A total of 129 adolescents aged 10-15 years were included in the study. OUTCOME MEASURES Fighting behavior, assault injury, weapon carrying, and aggressive behavior. RESULTS Higher retaliatory attitudes at baseline were associated with more aggression and a higher frequency of fighting over time. CONCLUSIONS Retaliatory attitudes may fuel cycles of violence among youth. Medical professionals in acute care settings have an opportunity to identify youths at risk of future assault injury by assessing retaliation, providing anticipatory guidance, and referring to intervention programs.

Neuromaturation and Adolescent Risk Taking: Why Development Is Not Determinism

In the January 2009 issue of this journal, Males argues that adolescent brain science perpetuates the “myth of adolescent risk taking.” He contends that those who study adolescent neuromaturation are biological determinists who ignore the profound social and environmental forces that influence adolescent behavior to further their own agendas. Males mischaracterizes developmental research and misinterprets public health data. This article analyzes his argument and provides a response based on the evidence. There is significant cross-species evidence that adolescence serves an important developmental function on the road to full maturation and is not merely an oppressive social construction. Research on neuromaturation can help elucidate both the vulnerabilities and tremendous potential of the adolescent brain. It also provides the opportunity to examine the role of social environments in shaping developmental processes and to explore how reasoned understandings of adolescent brain and biological development are being used to inform interventions that scaffold adolescent vulnerabilities.

Salivary cytokines as a minimally-invasive measure of immune functioning in young children: Correlates of individual differences and sensitivity to laboratory stress

There is growing interest in minimally-invasive measures of environmentally-responsive biological systems in developmental science. Contributing to that endeavor, this study explores the intercorrelations, correlates, and task-sensitivity of proinflammatory salivary cytokines in childhood. Saliva was sampled from 125 healthy five-year old children (49% male) across a series of cognitive and emotional challenge laboratory tasks. Samples were assayed for cytokines (IL-1β, IL-6, IL-8, TNFα), and markers of hypothalamic-pituitary-adrenal (HPA) and autonomic nervous system (ANS) activation (salivary cortisol and alpha-amylase [sAA]). Cytokines were positively intercorrelated and task-sensitivity varied. Except IL-8, cytokines were elevated in children with oral health issues and tobacco smoke exposure. Among boys, cytokines were positively related to sAA and negatively related to cortisol. The findings suggest that in healthy children, salivary cytokine levels reflect compartmentalized oral immune activity. Associations between ANS and HPA activity and cytokines in saliva may present opportunities for minimally-invasive methods to explore neuroendocrine-immune interactions during development.