Many exciting biomedical devices based on microtechnology have been introduced that provide solution to questions in biology, neuroscience, and medicine from engineer's perspective, such as silicon neural probes, massive MEA, and microfluidic chips. Among these devices, MEMS neural probes have shown promising results as next-generation neuroscience tool for small-animal experiments. Recently, few multi-functional silicon-based neural probes with extremely small dimensions have been presented. These probes not only allow one to monitor deep-brain neuronal activities of a mouse in real time but also allow one to deliver various stimulation modalities at the same time.