A system for aligning video‐recorded visual data and high‐quality multichannel recordings of simultaneously occurring signals

SUMMARY An electronic circuit is described which provides a unique number for each video frame, and which is superimposed on the frame as a 4-digit light-emitting diode display using a second camera and videomixer. The number is also encoded as a simple voltage waveform which is recorded separately together with electrical signals giving information about events related to, and coincident with, the visual data, for example nerve spike trains. Sophisticated computer analysis of signals can thus be related accurately to microscopical visual information processed by video analysis.