Perceived Social Support and Socioeconomic Status Predict Maternal Delay Discounting Behavior and Neural Function in Healthy Postpartum Women
Authors: Brents Lisa K , Young Jonathan , Knight Bettina T , Coker Jessica L , Ray‐Griffith Shona L , Stowe Zachary N , James G Andrew , Kilts Clint D 
Published: November 2023

Drug abuse disrupts maternal behavior, leading to poor mother‐child dyad outcomes. Important to maternal care is the ability to conceptualize, evaluate, and make decisions regarding temporally contingent consequences. One example of temporally contingent decision making is delay discounting, which is the normative tendency to devalue delayed rewards as the delay‐to‐reward increases. Individuals with substance use disorders exhibit an exaggerated preference for immediate rewards, even at a heavy discount, which likely thwarts drug abstinence. Maternal delay discounting behavior and its underlying neural mechanisms have not been studied in healthy or addicted populations. As a first step to understanding this executive function in addicted mothers, the present study focuses on the behaviors and neural representations of healthy mothers choosing temporally‐contingent gift card rewards for themselves and separately for their infants. We hypothesized that delay discounting (impulsive choice) in healthy mothers is correlated with intrinsic and social variables that are associated with maternal drug addiction, including increased maternal stress and lower socioeconomic status (SES), perceived social support (PSS), maternal‐infant bonding, and maternal conception and valuation of the future. Multiple regression models that predicted delay discounting behavior were further hypothesized to predict the neural correlates preceding each choice type (immediate or delayed). Postpartum women ages 15–45 with no current mood disorders or lifetime drug use disorders who were within 2 months of a full‐term delivery (n= 17) were assessed for the variables of interest and completed a functional magnetic resonance imaging (fMRI) scan while performing a delay discounting task on behalf of herself and on behalf of her infant. Impaired bonding and SES significantly (p < 0.007) predicted 44% of individual variance in delay discounting behavior for self. Controlling the model for PSS reduced the influence of impaired bonding and SES on choice preference. Together, these three variables significantly (p < 0.0009) predicted 64% of individual variance in a delayed choice‐specific activation in the right frontal pole, a prefrontal region important in prospective thought. In making decisions on behalf of one's infant, ethnicity and PSS significantly (p<0.002) predicted 51% of individual variance. Controlling the model for SES reduced the influence of ethnicity and PSS. This model explained 35% of individual variance in a delayed choice‐specific deactivation in the right dorsolateral prefrontal cortex, a region crucial to executive function. These results indicate that maternal PSS and SES play important roles in the behavior and neural function of postpartum maternal delay discounting.Support or Funding InformationSupport for this study was provided by the NIH (T32 DA022981 and P30 GM110702) and a grant from the BIRC Endowment Fund.