报告题目：Synaptic plasticity in prefrontal cortex: functional and dysfunctional regulations by dopamine
Center for Medical Education, Ryotokuji University, Chiba, JAPAN
摘要：The prefrontal cortex (PFC) is the brain site involved in executive cognitive function. Until about early 2000', a component of the executive function, i.e. short-term working memory, was widely focused as the main function of the PFC, which led to the view that the PFC is unrelated to long-term memory. We proposed that the function of PFC includes long-term memory; that is, memory of the temporal organization of behavior. We then proposed that the cellular substrate of this long-term memory is long-term synaptic plasticity in PFC neurons. We thus characterized PFC synaptic plasticity in terms of dopamine, the important neuromodulator for PFC function. First, we showed that the induction of long-term potentiation (LTP) is regulated by the level of tonic/background dopamine, where too low or too high background dopamine hampers LTP. Second, induction of long-term depression (LTD) is regulated by the level of the action of synaptically released dopamine, where the exaggeration of dopamine action by blocking dopamine transporter (DAT) activity blocks LTD. Thus, in the PFC, dopamine concentration-dependently regulates synaptic plasticity induction. We suggest that this dopaminergic regulation provides us with the insight into cellular mechanisms of certain psychiatric disorders, such as schizophrenia cognitive symptoms and drug addiction.