An alternative approach to increasing the functional capability of an integrated circuit chip other than the conventional scaling approach is presented and discussed. We will show the functional enhancement at a very elementary device level is essential in implementing intelligent functions at a system level. The concept of a four-terminal device is reviewed as a guiding principle in considering the device functionality enhancement. As an example of a four-terminal device, the neuron MOS transistor is presented. Applications of neuron MOS transistors to several new architecture circuits are demonstrated and the possibility of implementing intelligent functions directly on integrated circuit hardware is discussed.