The NL201 Spike Trigger Module is a gated amplitude discriminator for neuronal spike detection and detection of other events which produces separate output pulse trains for spikes which (i) cross the upper voltage threshold, (ii) cross the lower voltage threshold or (iii) cross the lower but not the upper threshold.

When it comes to the NL201 spike trigger, two potentiometers control window height and aperture settings. This module is often used in conjunction with the NL104A AC Preamplifier. The amplified signal from the NL104A is fed into the NL201 which can detect extracellular spikes and send an output pulse corresponding to each action potential.