TRANSMISSION AT A CENTRAL INHIBITORY SYNAPSE .4. QUANTAL STRUCTURE OF SYNAPTIC NOISE

Continuous segments of synaptic noise were recorded, in 12 experiments, from the voltage-clamped goldfish Mauthner (M-)-cell soma during depolarizations byond the Cl- equilibrium potential so that spontaneous inhibitory postsynaptic currents (IPSCs) were outward going, i.e., opposite in polarity to excitatory transients. Inhibitory components constituting the noise were detected with a program based on their expected waveforms, and their amplitude distributions were analyzed according to a quantal model to determine whether these responses, presumably because of asynchronous impulses in a population of presynaptic cells, were integral multiples of the same minimal unit.