Hippocampus
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People experiencing early-life stress (ELS) exhibit increased incidence of behaviors that lead to addiction and obesity as adults. Many of these behaviors may be viewed as resulting from an overreliance on habits as opposed to goal-directed instrumental behavior. This increased habitization may result from alterations in the interactions between dorsolateral striatum-dependent and hippocampus-dependent learning systems. ⋯ In the high-ELS group, we observed a reduced sensitivity to reinforcement schedule even in the absence of the declarative memory challenge, consistent with Experiment 1. Our results suggest that ELS reduces the tendency to use declarative, hippocampus-dependent memory in instrumental tasks in favor of habits. ELS may affect hippocampal development, thus altering the interaction between memory systems and potentially contributing to poor health outcomes.