Automatic detection, characterization, and discrimination of kinetically distinct spontaneous synaptic events

Rapid and reliable detection of randomly occurring small amplitude synaptic events resulting from activation of different classes of ligand-gated rece ptors is a difficult task. Here, we describe and characterize an amplitude threshold algorithm, written as an IGOR Pro procedure, which detects events as well as characterizes their amplitudes and kinetics. The program was de veloped to analyze recording traces that each contained both excitatory (gl utamate-mediated) and inhibitory (GABA and glycine-mediated) events. By usi ng differences in kinetics, the program could discriminate between the two different classes of events. In summary, the program has the following stre ngths: (I) it is generally applicable to circumstances in which different p opulations of elementary events occur concurrently, a drawback of methods t hat employ matched filtering techniques, (2) it is relatively insensitive t o drifts in baseline, and (3) it generates user-accessible arrays of the ti ming, amplitude and kinetic parameters of the detected events, making custo mized statistical analysis of event characteristics easily executable. (C) 1999 Elsevier Science B.V. All rights reserved.