1. A neuron element with electrically programmable synaptic weight for an artificial neural network comprising: an excitatory-connected floating-gate transistor having a floating gate, a control gate electrode for receiving an input signal, a drain electrode for connection to a power source voltage, a source electrode for connection to an output line, and a programming electrode connected to said source electrode, said control gate electrode and said programming electrode being utilized to program the threshold voltage of said excitatory-connected floating-gate transistor, and thus the synaptic weight of said neuron element; and an inhibitory-connected floating-gate transistor having a floating gate, a control gate electrode to receive said input signal, a drain electrode connected to said source electrode of said excitatory-connected floating-gate transistor, a source electrode for connection to ground, and a programming electrode, said control gate electrode and said programming electrode of said inhibitory-connected floating-gate transistor being utilized to program the threshold voltage of said inhibitory-connected floating-gate transistor, and thus the synaptic weight of said neuron element.