Slipsliding away

Changes in the synaptic strength of neurons, effected by repeated neuronal activity, drive important behavioral processes such as learning and memory. Continuous simulation of a neuron, for example, can alter the signaling or molecular architecture at its synapses, and make it easier—or harder—for that neuron to activate other neurons with which it communicates. Synaptic efficacy can be enhanced by increasing the process known as excitatory neurotransmission, or by decreasing its opposing process, inhibitory neurotransmission. These processes trigger or halt the firing of neurons, respectively. Now, an international team of researchers, including Hiroko Bannai at the RIKEN Brain Science Institute in Wako, has shown that neuronal activity drives inhibitory neurotransmitter receptors to diffuse away from the synapse, which substantially reduces inhibitory neurotransmission at those synapses1. In many parts of the brain, inhibitory neurotransmission is mediated by a molecule called γ-aminobutyric acid (GABA) binding to its receptors at synapses. When the researchers induced neuronal activity in cultured neurons, they found fewer GABA receptors—and fewer GABA receptor scaffolding molecules—at the synapses of these neurons. This resulted in less efficient inhibitory neurotransmission owing to smaller inhibitory electrical currents through these receptors. read more at Riken's.....