VISUALIZATION OF QUANTAL SYNAPTIC TRANSMISSION BY DENDRITIC CALCIUM IMAGING

As changes in synaptic strength are thought to be critical for learnin g and memory, it would be useful to monitor the activity of individual identified synapses on mammalian central neurons. Calcium imaging of cortical neurons grown in primary culture was used to visualize the ac tivation of individual postsynaptic elements by miniature excitatory s ynaptic currents elicited by spontaneous quantal release. This approac h revealed that the probability of spontaneous activity differed among synapses on the same dendrite. Furthermore, synapses that undergo cha nges in activity induced by glutamate or phorbol ester treatment were identified.