The Longevity of Hippocampus-Dependent Memory Is Orchestrated by the Locus Coeruleus-Noradrenergic System

Figure 1

Priming of hippocampus-based memory via locus coeruleus activation. The ventral tegmental area (VTA) and LC are interlinked by fiber projections [35]. After locus coeruleus (LC) activation, noradrenaline (NA) and dopamine (DA) are released in the dentate gyrus of the hippocampus from LC terminals [11, 13]. The LC projects also to the CA1 and CA3 region of the hippocampus [82]. The main mechanisms involved in how memory is primed by NA and DA are indicated in boxes at specific hippocampal subregions [25–28, 33, 63, 72]. Moreover, two other brain structures such as the basolateral amygdala (BLA) and the prefrontal cortex (PFC) receive projections from the LC [3, 4] and participate in noradrenergic and dopaminergic modulation of hippocampus-based memory [6, 49, 61]. BLA = basolateral amygdala, DG = dentate gyrus, HPC = hippocampus, LC = locus coeruleus, LTP = long-term potentiation, LTD = long-term depression, PFC = prefrontal cortex, SWRs = sharp wave ripples, VTA = ventral tegmental area.