Minicomputer identification and timing of nerve impulses mixed in a single recording channel

Abstract

The use of a minicomputer on-line to identify and measure the time series of different nerve impulses mixed in a single recording channel is described. The study involves electrical discharges recorded simultaneously from two of the olfactory receptors found on the antenna of the male red-banded leaf roller moth. These receptor cells were stimulated by odors normally secreted by the female which have been shown to act as powerful sex attractants to the male. The computer program stores the time interval between nerve spikes and 30 100-µs samples of the waveform of each spike detected. An ensemble of up to 1000 sets of samples can be stored in the course of an experiment on a 32K-word magnetic disk, through a data channel facility. A statistic is calculated on the sampled data for each spike in the ensemble. The range in values of this statistic is used to characterize the data by plotting a histogram of the nerve-spike parameter. This display can then be partitioned so as to identify the two units of interest. On the basis of this identification, a distinct time series for each receptor is computed and filed on the minitape for further data analysis.