Dopamine as a Potential Target for Learning and Memory: Contributing to Related Neurological Disorders

It is well established that learning and memory are complex processes. They involve and recruit different brain modulatory neurotransmitter systems. Considerable evidence points to the involvement of dopamine (DA) in learning and memory. Manifestations of the synaptic spatial localization of the effect of DA have gained a great deal of interest. Despite the molecular cloning of the five DA receptor subtypes, the underlying signaling of the DA receptors in spatial learning and memory is less compelling. Fluctuations in the DA level in the brain are associated with many diseases that comprise deficits in learning and memory, including Parkinson's disease, Huntington’s disease, schizophrenia, and Alzheimer's disease. This review aims to briefly summarize existing information regarding the memory performance modified by DA. The signaling of the DA system, particularly examining the origin of DA-modulated memory, is also discussed. Then, several kinds of memories in which DA plays a critical role, including reward signaling, working memory, and long-term plasticity, as well as memory consolidation, are also described. Finally, memory impairment in some DA-related neurological disorders is also examined.