Salk Institute MNL/S
Synaptic transmission in the cortex is surprisingly unreliable: at some synapses, the failure rate can be or higher, so that fewer than one out of every ten presynaptic impulses leads to a postsynaptic response. Furthermore, even the size of the response when it occurs is highly variable. This stochasticity is an intrinsic and fundamental property of synaptic transmission, but it is not considered in most theories of cortical function which assume that brain components are reliable. In my talk I will discuss the sources of synaptic unreliability. In particular, I will focus on the rapid modulations of release probability that underlie short term plasticity, and suggest that synaptic unreliability may be the price necessary to achieve connections with a large dynamic range on very short time scales.