A growing body of research has examined the impact of childhood adversity on neural structure and function. Advances in our understanding of the neurodevelopmental consequences of adverse early environments require the identification of dimensions of environmental experience that influence neural development differently and mechanisms other than the frequently-invoked stress pathways. We propose a novel conceptual framework that differentiates between deprivation (absence of expected environmental inputs and complexity) and threat (presence of experiences that represent a threat to one’s physical integrity) and make predictions grounded in basic neuroscience principles about their distinct effects on neural development. We review animal research on fear learning and sensory deprivation as well as human research on childhood adversity and neural development to support these predictions. We argue that these previously undifferentiated dimensions of experience exert strong and distinct influences on neural development that cannot be fully explained by prevailing models focusing only on stress pathways. Our aim is not to exhaustively review existing evidence on childhood adversity and neural development, but to provide a novel framework to guide future research.

Research on childhood adversity has traditionally focused on single types of adversity, which is limited because of high co-occurrence, or on the total number of adverse experiences, which assumes that diverse experiences influence development similarly. Identifying dimensions of environmental experience that are common to multiple types of adversity may be a more effective strategy. We examined the unique associations of two such dimensions (threat and cognitive deprivation) with automatic emotion regulation and cognitive control using a multivariate approach that simultaneously examined both dimensions of adversity. Data were drawn from a community sample of adolescents (N = 287) with variability in exposure to violence, an indicator of threat, and poverty, which is associated with cognitive deprivation. Adolescents completed tasks measuring automatic emotion regulation and cognitive control in neutral and emotional contexts. Violence was associated with automatic emotion regulation deficits, but not cognitive control; poverty was associated with poor cognitive control, but not automatic emotion regulation. Both violence and poverty predicted poor inhibition in an emotional context. Utilizing an approach focused on either single types of adversity or cumulative risk obscured specificity in the associations of violence and poverty with emotional and cognitive outcomes. These findings suggest that different dimensions of childhood adversity have distinct influences on development and highlight the utility of a differentiated multivariate approach.

Alterations in learning processes and the neural circuitry that supports fear conditioning and extinction represent mechanisms through which trauma exposure might influence risk for psychopathology. Few studies examine how trauma or neural structure relates to fear conditioning in children. Children (n=94) aged 6-18 years, 40.4% (n=38) with exposure to maltreatment (physical abuse, sexual abuse, or domestic violence), completed a fear conditioning paradigm utilizing blue and yellow bells as conditioned stimuli (CS+/CS-) and an aversive alarm noise as the unconditioned stimulus. Skin conductance responses (SCR) and self-reported fear were acquired. Magnetic resonance imaging data were acquired from 60 children. Children without maltreatment exposure exhibited strong differential conditioning to the CS+ vs CS-, based on SCR and self-reported fear. In contrast, maltreated children exhibited blunted SCR to the CS+ and failed to exhibit differential SCR to the CS+ vs CS- during early conditioning. Amygdala and hippocampal volume were reduced among children with maltreatment exposure and were negatively associated with SCR to the CS+ during early conditioning in the total sample, although these associations were negative only among non-maltreated children and were positive among maltreated children. The association of maltreatment with externalizing psychopathology was mediated by this perturbed pattern of fear conditioning. Child maltreatment is associated with failure to discriminate between threat and safety cues during fear conditioning in children. Poor threat-safety discrimination might reflect either enhanced fear generalization or a deficit in associative learning, which may in turn represent a central mechanism underlying the development of maltreatment-related externalizing psychopathology in children.

Exposure to trauma in childhood is associated with elevated risk for multiple forms of psychopathology. Here we present a biopsychosocial model outlining the mechanisms that link child trauma with psychopathology and protective factors that can mitigate these risk pathways. We focus on four mechanisms of enhanced threat processing: information processing biases that facilitate rapid identification of environmental threats, disruptions in learning mechanisms underlying the acquisition of fear, heightened emotional responses to potential threats, and difficulty disengaging from negative emotional content. Supportive relationships with caregivers, heightened sensitivity to rewarding and positive stimuli, and mature amygdala-prefrontal circuitry each serve as potential buffers of these risk pathways, highlighting novel directions for interventions aimed at preventing the onset of psychopathology following child trauma.