The nucleus locus coeruleus modulatory effect on memory formation: A literature review

The nucleus locus coeruleus (LC), the main source of norepinephrine in the brain, is connected to memory processing regions such as the hippocampus and baso-lateral amygdala (BLA). The LC and its mostly associated noradrenergic projections, play an important role in memory formation parallel to other neurotransmitter systems. It has been suggested that the unique response characteristics of LC to various situations strengthens different memories formation. Here, we review key related findings of LC effect on memory (avoidance, spatial, cognitive) formation, memory processing regions, memory molecular mechanisms as well as its role in memory related disorders. Literature review was conducted by extensive search on ISI, PubMed and Scopus, online databases from May ۲۰۲۱ to July ۲۰۲۱. According to the obtained results, LC noradrenergic projections to memory processing areas of the brain, can modulate the encoding, consolidation, and retrieval for different memory types. Also, the LC regulates neurogenesis and neural plasticity in different areas of the brain. Evidences suggested that dysfunction of the LC and its associated noradrenergic system may lead to cognitive impairment or a variety of memory-related disorders, including Alzheimer's disease. Finally, it can be concluded that the locus coeruleus noradrenergic system may be a suitable target for the treatment of different memory/cognitive disorders.