A Delayed Wave of c-Fos Expression in the Dorsal Hippocampus is Involved Specifically in Persistence of Long-term Memory Storage

KATCHE C; BEKINSCHTEIN P; SLIPCZUK L; GOLDIN A; IZQUIERDO I; CAMMAROTA M; MEDINA JH

Huerta Grande - Cordoba

Workshop; IRCN; 2009

The most remarkable feature of the brain is its capacity to collect and store information to produce appropriate changes in behavior. Memory is a temporally graded process during which transcription and translation steps are required in the first hours after acquisition. Although persistence is a key characteristic of memory storage, little is known about its mechanisms. Here, we show that long-lasting but not short-lived inhibitory avoidance (IA) long-term memory (LTM), is associated with a delayed expression of c-Fos in the hippocampus. Importantly, this late wave of c-Fos is necessary for maintenance of IA LTM storage. Moreover, inhibition of transcription in the dorsal hippocampus 24 h after training hinders persistence, but not formation of LTM. These findings indicate that a delayed phase of transcription is essential for maintenance of a hippocampus-dependent memory trace. Our results support the hypothesis that recurrent rounds of consolidation-like events take place late after learning in the dorsal hippocampus in order to maintain memories.