Different implications of the dorsal and ventral hippocampus on contextual memory retrieval after stress

This study assessed the relative contributions of dorsal (dHPC) and ventral (vHPC) hippocampus regions in mediating the rapid effects of an acute stress on contextual memory retrieval. Indeed, we previously showed that an acute stress (3 electric footschocks; 0.9 mA each) delivered 15 min before the 24h‐test inversed the memory retrieval pattern in a contextual discrimination task. Specifically, mice learned in a four‐hole board two successive discriminations (D1 and D2) varying by the color and texture of the floor. Twenty‐four hours later, non‐stressed animals remembered accurately D1 but not D2 whereas stressed mice showed an opposite memory retrieval pattern, D2 being more accurately remembered than D1. We showed here that, at the time of memory testing in that task, stressed animals exhibited no significant changes neither in pCREB activity nor in the time‐course evolution of corticosterone into the vHPC; in contrast, a significant decrease in pCREB activity and a significant increase in corticosterone were observed in the dHPC as compared to non‐stressed mice. Moreover, local infusion of the anesthetic lidocain into the vHPC 15 min before the onset of the stressor did not modify the memory retrieval pattern in non‐stress and stress conditions whereas lidocaine infusion into the dHPC induced in non‐stressed mice an memory retrieval pattern similar to that observed in stressed animals. The overall set of data shows that memory retrieval in non‐stress con...
Source: Hippocampus - Category: Neurology Authors: Tags: Research Article Source Type: research