Simple circuit for artificial spiking neuron (brain cell), loosely based on Hodgkin-Huxley model.
Circuit implements leaking integrate-and-fire mechanism.
Push button on the left side of the circuit represents input - SYNAPSE. Input current is integrated until threshold (600mV in artificial neuron, -60mV in real neuron) is reached, then neuron fires producing ACTION POTENTIAL (2V in artificial neuron, 100mV in real neuron). Next, neuron is temporarily deactivated and does not react to input - REFRACTORY PERIOD. Input current constantly leaks from the cell membrane driving cell towards RESTING potential (0V in artificial neuron, -75mV in real neuron).
Load resistor and voltmeter on the right side represent output - AXON.
Demonstration:
HOLD push button to inject input current. Observe resulting voltage spikes (green line) on the load resistor. Continuos injection of the current will result in oscillation - so called SPIKE TRAIN.
Next:
SEARCH for "Tiny Neural Network" circuit with 3 of these neurons interconnected.
