Neuroscience Update

Neurons transmit electrical signals as the basis of infor-mation processing in the nervous system. Chemical synapses mediate much of the communication between neurons. Synapses pivotally influence the flow of infor-mation throughout the neural network and are primary sites of malleability that may underlie behavioral altera-tions and memory formation. Modulation of synaptic strength takes many forms. One form includes mature, functioning synapses rendered dormant, but the mecha-nisms underlying this are poorly understood. These “silent ” synapses are deficient either in neurotransmitter release or in postsynaptic receptors (Fig. 1). Here, we will focus on presynaptically silent synapses, as postsynapti-cally silent synapses have been discussed extensively elsewhere (Kerchner and Nicoll 2008). Presynapticall