The information we gather throughout the course of our lives—the quickest way to get to work, for instance, or the name of a friend’s new partner—is stored in synapses. In the adult brain, new synapses are thought to be formed from scratch as needed or through the modification of existing connections. Now, a study published November 30 in Nature unearths an abundance of ready-made ‘silent synapses’ which ripen upon neuronal stimulation.
Silent synapses are otherwise complete neuronal connections that lack a key signaling protein—AMPA receptors—that renders them inactive. They were thought to be unique to early development, as previous work found that the silent connections vanish by the time a mouse has reached adulthood. But researchers may have been looking in the wrong place. In young animals, silent synapses are formed from larger protrusions called dendritic spines. But in adults, they can be found on the ends of threadlike structures ...
