Glucose modulates recently reactivated memories

Abstract

A passive avoidance to active avoidance negative transfer paradigm was used to investigate the effects of glucose on recently acquired and recently reactivated memories. Immediate post-passive avoidance training injections of glucose (100 mg/kg s.c.) improved memory and thus interfered with the rats’ ability to learn the one-way active avoidance task 24 h later. Rats receiving a memory reactivation treatment 24 h after passive avoidance training showed greater negative transfer to the active avoidance task presented 24 h later than did nonreactivated control animals. Furthermore, the administration of glucose (32, 100, or 320 mg/kg) following memory reactivation proactively interfered with the acquisition of the active avoidance; this effect followed an inverted U-shaped dose-response function. The ability of glucose (100 mg/kg) to alter the reactivated passive avoidance memory decreased as the interval between reactivation and glucose treatment was increased up to 30 min. These results demonstrate that glucose modulates the processing of old memories that have been recently reactivated, just as it modulates the processing of new memories that have been recently acquired.