Creating diverse synapses from the same molecules

Research over the past half a century has revealed remarkable diversity among chemical synapses of the CNS. The structural, functional and molecular diversity of synapses was mainly concluded from studying different synapses in distinct brain regions and preparations. It is not surprising that synapses made by molecularly distinct pre-synaptic and post-synaptic cells display different morphological and functional properties with distinct underlying molecular mechanisms. However, synapses made by a single presynaptic cell onto distinct types of postsynaptic cells, or distinct presynaptic inputs onto a single postsynaptic cell, also show remarkable heterogeneity. Here, by reviewing recent experiments, I suggest that robust functional diversity can be achieved by building synapses from the same molecules, but using different numbers, densities and nanoscale arrangements.