With the available data of huge samples of contiguous-scales both for healthy controls and patients including depression, autism and schizophrenia etc, we are in the position to quantify human brain activities such as creativity, happiness, IQ and EQ etc and search the roots of various mental disorders. With novel mathematical and machine learning approaches, we first introduced functional entropy and entropy rate of resting state to characterize the dynamic behaivour of our brain. It is further found that the functional entropy is an increasing function of age, but a decreasing function of creativity and IQ. Its biological mechanisms are explored. With the brain wide associate study approach, for the first time in the literature we are able to identify the roots of a few mental disorders. For example, for depression, we found that the most altered regions are located in the lateral and medial orbitofrontal cortex for punishment and reward. Follow-up rTMS at the lateral orbitofrontal cortex demonstrated significant outcomes of the treatments. Finally we discuss some of our recent results on brain-inspired AI and their applications.