Producing spike-timing dependent plasticity in an ultra-dense synapse cross-bar array

A system for producing spike-timing dependent plasticity, comprising:

• a processor;
• a plurality of electronic neurons, wherein each electronic neuron is configured to:
• send an alert pulse to each connected electronic neuron when the electronic neuron spikes,
• send a gate pulse from the spiking electronic neuron to each connected electronic neuron when the spiking electronic neuron sends the alert pulse, and
• send a response pulse from each electronic neuron receiving the alert pulse to the spiking electronic neuron;
• and
• a cross-bar array coupled to the plurality of electronic neurons and configured to interconnect the plurality of electronic neurons;
• wherein an alert pulse from a spiking electronic neuron notifies each connected electronic neuron that said spiking electronic neuron is sending a gate pulse to said connected electronic neuron, and triggers said electronic neuron to read a state of said electronic neuron, wherein said electronic neuron sends a response pulse having an amplitude based on the state of said electronic neuron;
• wherein the cross-bar array comprises a plurality of variable state resistors;
• wherein each variable state resistor is at a cross-point junction, the cross-point junction is coupled between two electronic neurons;
• and
• wherein each variable state resistor is configured to increase or decrease conductance as a function of time since a last spiking of the electronic neuron receiving the alert pulse.