Individuals developing in impoverished environments are at heightened risk for a host of physical and mental health difficulties across the life span (Shonkoff et al., 2012). Studies indicate that children living in poverty are at increased risk for subsequent aggression, oppositional behavior, and other forms of externalizing psychopathology (Piotrowska, Stride, Croft, & Rowe, 2015). These negative outcomes are likely due to the multiple risk factors associated with poverty, and persist into adulthood (Jensen, Berens, & Nelson, 2017). Childhood hardship is associated with a higher probability of first‐onset mood, behavioral, and substance abuse disorders at all stages of the life course (McLaughlin et al., 2011), even when controlling for income levels in adulthood (Evans & Cassells, 2014). Furthermore, quasi‐experimental work where annual income was supplemented has found moving families out of poverty specifically reduced children's symptoms of conduct and oppositional defiant disorders (Costello, Compton, Keeler, & Angold, 2003).

Even though these consistent links exist, not all children living in poverty will develop externalizing psychopathology. Indeed, research has begun to identify many potential markers of risk and resiliency. From a psychosocial perspective, differences in self‐regulation may be important for understanding the circumstances under which poverty does (and does not) become connected to externalizing outcomes (Blair & Raver, 2015; Evans & Kim, 2012). Self‐regulation is a multifaceted constellation of skills that enables the control of attention and emotion, for the purposes of setting, maintaining, and achieving goals (Bridgett, Burt, Edwards, & Deater‐Deckard, 2015; Nigg, 2016). A growing body of longitudinal studies have found that better self‐regulation in childhood is related to fewer externalizing problems, including lower rates of antisocial personality disorder, less interpersonal conflict, and reduced likelihood of being involved in criminal activity (Caspi, Moffitt, Newman, & Silva, 1996; Moffitt et al., 2011). In the aggregate, poverty is associated with lower self‐regulation abilities, but there is considerable variability in these traits within low socioeconomic status (SES) populations (Blair & Raver, 2012, 2015; Montroy, Bowles, Skibbe, McClelland, & Morrison, 2016). In addition, there is consistent evidence of protective effects, whereby individuals from low SES backgrounds with better self‐regulatory skills have lower rates of externalizing psychopathology compared with their demographically similar peers (Buckner, Mezzacappa, & Beardslee, 2003; Flouri, Midouhas, & Joshi, 2014; Lengua, Bush, Long, Kovacs, & Trancik, 2008).

Neurobiologically informed research has similarly begun to identify brain markers of risk and resiliency. Using neuroimaging, many studies have reported structural differences in the hippocampus and ventromedial portions of the prefrontal cortex (vmPFC) in relation to exposure to aspects of poverty, including lower household income and social status (Gianaros et al., 2007; Hanson, Chandra, Wolfe, & Pollak, 2011; Hanson et al., 2015; Noble et al., 2012, 2015). Past research implicates both of these brain structures as important for socioemotional functioning (Davidson & McEwen, 2012). Interestingly, structural differences in the hippocampus and vmPFC appear to mediate the relation between childhood poverty and externalizing symptoms, with smaller volumes in each region relating to greater problem behaviors (Hanson et al., 2015; Holz et al., 2014). Few studies have, however, examined resting state functional connectivity, with the preponderance of past work focused on brain structure in relation to exposure to aspects of poverty. One exception is a recent study by Sripada, Swain, Evans, Welsh, and Liberzon (2014) that found childhood poverty was related to reduced resting state functional connectivity between the hippocampus, the vmPFC, and the posterior cingulate.

The limited work examining functional brain interactions is a major limitation, as complex behavioral processes likely arise through multiple brain regions interacting and sharing information with each other (van den Heuvel & Pol, 2010). With the hippocampus and vmPFC, functional interactions between these regions may be important for using previously acquired information in goal‐directed behavior (Murty, Calabro, & Luna, 2016). For example, Gluth, Sommer, Rieskamp, and Büchel (2015) showed that decision making is limited by memory constraints, and this is associated with functional connectivity between the hippocampus and vmPFC. Studies using resting state connectivity could fill in these important gaps and provide new insights about the impact of experience on brain organization. Spontaneous brain activity (assessed at rest) is highly correlated between multiple brain regions, predicts task‐response properties of neural circuits, and can identify subjects’ aptitude for different cognitive tasks (Fox & Greicius, 2010).

Turning back to self‐regulation, although this characteristic can exert protective effects, it is not a fixed trait and this may have major implications for developmental outcomes. Psychosocial interventions have uniquely noted that improving parenting practices facilitates children's early development of self‐regulation, and this can then serve as a foundation for positive functioning in multiple domains and contexts (Brody et al., 2011; Chang, Shaw, Dishion, Gardner, & Wilson, 2014). One notable example is the Strong African American Families (SAAF) intervention—a family skills training program aimed at mitigating the negative effects of poverty and life stress on rural African American youths through a focus on youths, parents, and their family interactions (Brody, 2016). This intervention identified malleable, proximal parenting processes in a youth's immediate family context that could facilitate the development of responsive–supportive parent–child relationships; these supportive relationships could then enhance children's development of self‐regulation. In keeping with models of developmental cascades (Masten & Cicchetti, 2010), changes in parenting may cause youth: to adopt parental norms, develop the ability to govern their own behavior in the absence of external supervision, and approach stressful life events through direct action rather than through avoidance or anger. Past work (e.g., Brody, Murry, & McNair, 2005) has found support for these ideas, noting that intervention‐induced changes in parenting were linked with changes in responsive–supportive parent–child relationships and then youth self‐regulation. In addition to changes in self‐regulation, this intervention has been found to exert strong and longlasting effects on a host of other psychosocial outcomes—with major reductions in conduct problems and lessened alcohol use after participation in the program (Brody, Chen, Kogan, Murry, & Brown, 2010; Brody, Kogan, Chen, & Murry, 2008). Importantly, these effects were found long after completion of the program, with differences seen 2–5 years after intervention delivery. In addition, nearly a decade after the program, differences in inflammation and other health‐related biomarkers have been found for participants compared to controls (Brody, Yu, & Beach, 2016). Collectively, these findings underscore that fostering positive parenting can yield important self‐regulatory gains in children. Changes in self‐regulation may buffer against the psychosocial disadvantages that beset children in poverty and can foster positive mental health, as well as physical, outcomes. Indeed, these self‐regulatory gains could carry forward, facilitating exposure to more stimulating experiences across development that promote brain connectivity and other positive patterns of neurobiology.

Interestingly, in recent neurobiological work in the SAAF cohort, the intervention was found to bolster against the adverse effects of poverty. In this work, and similar to other studies, years spent in poverty during childhood were associated with smaller adult hippocampal volumes; however, in those who completed the intervention, this relation was not seen, suggesting exposure to prevention programming in childhood could have lasting protective effects on brain development into adulthood (Brody et al., 2017). Paralleling preclinical work, smaller volumes were found in the dentate gyrus (DG) for individuals living in poverty who did not complete the intervention. Alterations in the DG are notable for a number of reasons. The DG is central to pattern separation and completion, processes that aid in adaptively guiding behavior (Nakashiba et al., 2012). More broadly, the DG is associated with affective regulation and the pathophysiology of mood disorders, contributing to stress and emotional responses, and serving as the main gateway of information for the other portions of the hippocampus (Fa et al., 2014).

Here, we return to the SAAF study to investigate links between a psychosocial intervention, neurobiology, and the behavioral gains instilled by this preventive programming. Given that this randomized control trial was designed to increase self‐regulatory abilities in low‐SES African Americans from the rural South, we first probed whether childhood self‐regulation was improved in a subsample of intervention participants who were recontacted later in adulthood (Hypothesis 1). We, next, examined resting state functional brain differences related to participation in the SAAF program. Given the recent results noting structural brain differences in the DG in SAAF participants, we set out to investigate potential alterations in the resting state connectivity of this hippocampal subregion related to SAAF. On the basis of the past research findings, we predicted that the intervention would be related to increased functional connectivity between the DG and vmPFC in the intervention group, compared to control participants (Hypothesis 2). We, next, centered in on the behavioral target of the SAAF intervention, namely developmental gains in self‐regulation. Given that SAAF improved this capacity during development, we wanted to investigate if gains in self‐regulation (instilled by the intervention) would mediate the group differences in functional connectivity (Hypothesis 3). This would be an initial step to understand the developmental factors potentially influencing neurobiological differences in adulthood. We finally, aimed to connect developmental gains, neurobiology, and present‐day behavior by examining relations between brain connectivity, self‐regulatory gains, and present‐day externalizing problems. Motivated by past research, we predicted that higher connectivity between the DG and vmPFC would be related to lessened present‐day externalizing problems (Hypothesis 4).