Differential expression of plasticity-related genes in waking and sleep and their regulation by the noradrenergic system

Behavioral studies indicate that the ability to acquire long-term memories is severely impaired during sleep. It is unclear, however, why the highly s ynchronous discharge of neurons during sleep should not be followed by the induction of enduring plastic changes. Here we show that the expression of phosphorylated CRE-binding protein, Arc, and BDNF, three genes whose induct ion is often associated with synaptic plasticity, is high during waking and low during sleep. We also show that the induction of these genes during wa king depends on the activity of the noradrenergic system, which is high in waking and low in sleep. These molecular results complement behavioral evid ence and provide a mechanism for the impairment of long-term memory acquisi tion during sleep.