Infralimbic Cortex biases Preference Decision Making for Offspring over Competing Cocaine Associated Stimuli in New Mother Rats

Abstract

In the context of drug abuse, converging evidence suggests that cocaine use in new mothers is significantly reduced by the competing motivation related to child rearing. Given the demonstrated importance of the medial prefrontal cortex (mPFC) in decision making processes, we investigated the contribution of distinct regions of the mPFC (anterior cingulate, prelimbic, infralimbic) to decision-making in new mother rats performing a concurrent pup/cocaine choice conditioned place preference (CPP) task. When given a choice, inactivation of infralimbic cortex significantly biased decision-making of mother rats towards cocaine-associated cues, highly contrasting the distribution of preferences by control groups. In contrast, inactivation of prelimbic cortex had the opposite effect, significantly increasing offspring bias in the decision making, such that none of mothers chose the cocaine-associated alternative. Anterior cingulate inactivation was without effect. Functional inactivation of these same mPFC subregions had no effect in a non-conflict CPP task in which context-induced cocaine or pup seeking were examined separately. Notably, inactivation of the infralimbic cortex also interfered with maternal behavior. Taken together, we have identified a specific role of the infralimbic cortex in the prioritization of offspring over drug competing alternatives, thus promoting resistance to drug use in new mothers.

Significant Statement Cocaine use by postpartum women is a serious health problem that has a tragic impact on the mother’s ability to properly care for her child, with life-long consequences for both the mother and her child. Here we show that in the context of new motherhood, the infralimbic cortex biases decision making toward offspring stimuli over cocaine seeking in new mothers. These findings provide novel information about how the maternal brain processes information about offspring and how this information is integrated to bias decision-making. Considering the major impact of maternal cocaine use on both mother and child health, understanding how maternal motivation can provide resistance to drug use is highly pertinent.