It is proposed that the consolidation and reconsolidation of memories are based on a behavioral tagging and capture process. That is, the setting of a tag at the appropriate neural substrate during learning, or memory reactivation, ensures the stabilization of the trace upon the capture of newly synthesized proteins (PRPs). Also, dopamine and noradrenaline have been considered neuromodulators in various processes, including memory. Here, we studied whether these neurotransmitters and their main sources (Ventral Tegmental Area -VTA- and Locus coeruleus-LC-) act on memory by regulating the synthesis of PRPs on brain structures where they will be stored.
We show that coupling the activation of the VTA to a training in the spatial object recognition task, or the reactivation of its memory, ensures the stabilization of the memory trace, otherwise impaired by the administration of protein synthesis inhibitors during learning or reconsolidation. This process relies on the function of hippocampal dopaminergic receptors and subsequent protein synthesis. Similar findings are reported for the LC and the β-adrenergic receptors, along with further insights on these neurotransmitter systems functions.
In summary, our results suggest that the VTA and the LC act over the hippocampus via the D1/D5-dopaminergic and the β-adrenergic receptors, thus regulating the synthesis of the PRPs required for memory stabilization; revealing a way in which neuromodulator systems regulate lasting memories.