The present study examined the role of the stria terminalis in modulating the memory enhancement produced by posttraining intracaudate nucleus injection of oxotremorine. Male Sprague-Dawley rats with either sham operations or bilateral lesions of the stria terminalis (ST) were trained on a one-trial inhibitory-avoidance task and received a unilateral posttraining intracaudate injection of either a buffer vehicle or the cholinergic agonist oxotremorine (0.3 microg/0.5 microl) into a medial region of the caudate nucleus innervated by the ST. Intracaudate injection of oxotremorine improved memory in sham-operated rats. Although ST lesions did not affect retention in rats given intracaudate injections of the buffer vehicle, ST lesions attenuated the memory enhancement produced by posttraining intracaudate injection of oxotremorine. In view of anatomical evidence indicating that amygdalostriatal projections are nonreciprocal, the present findings suggest that amygdala output via the ST is essential for memory enhancement produced by intracaudate injection of oxotremorine.