Are steady-state temporal correlations between evoked stochastic releases of synaptic vesicles as informative as suggested?

摘要

Using a stochastic model, we found that the steady-state temporal correlation between synaptic responses evoked by successive presynaptic spikes under conditions of high-frequency repetitive stimulation (50–100 sec?1) is always negative. Therefore, the sign of this correlation cannot be used as a criterion that allows one to distinguish the univesicular vs multivesicular modes of neurotransmitter release in an active zone or the univesicular releases with low vs high probabilities of vesicle release, as suggested earlier [7]. For lower stimulation frequencies (15–20 sec?1), positive correlation between release events evoked by consecutive stimuli is observed only in those cases where the number of ready-releasable vesicles and the time constant of recovery from depression are sufficiently large.