A two-neuron cross-correlation circuit with a wide and continuous range of time delay

We describe a circuit of two spiking neurons which extracts mathematically accurate cross-correlations from the signal inputs. It differs from prior circuits such as coincidence detectors or enhanced motion detectors in that it does not require an a priori fixed delay between input signals to be selected. The output, in the form of a differential spike histogram, displays a mathematical cross-correlation in the conventional correlation vs. time form.