Despite the lack of morphine-induced changes in the social interaction test, a higher percentage of oxytocin-immunoreactive neurons within the hypothalamic paraventricular nucleus of morphine-exposed mice correlated with decreased time spent interacting with the unknown mouse in the social interaction test (A). Although Tat also did not change the overall oxytocin or CRF levels or social behaviors, in Tat(+) mice, hippocampal oxytocin levels positively correlated with time spent interacting with the novel unknown mouse in the social novelty test (B). In the social interaction test, higher amygdalar CRF levels in Tat(+) mice correlated with an increased latency to interact (C) and decreased time spent interacting (D) with the unknown mouse. The latency to interact and time spent interacting with the unknown mouse also positively correlated with PFC (E) and hippocampal (F) CRF levels, respectively. n = 8 mice per group.