**4. Conclusion**

In this chapter, we have attempted to link structural and functional findings of developmental studies to PFC. Our knowledge and understanding of the neural mechanisms, a growing body of evidence, point to the PFC as a central regulator. The review of the developmental literature indicates that, in the child, the cognitive and emotional functions of the prefrontal cortex develop in apparent synchrony with its structural maturation. The long-term development of executive functions is likely to be aligned with neurophysiological changes, particularly synaptogenesis and myelination in the prefrontal cortex.

All of cognitive functions seem to reach a relative plateau of maturity at about the age of 12 years. For example, development of attention reach maturity at about age 12, Working memory and planning seem to develop also at the same pace and toward the same plateau (about 12 years). Temporal integration development depends on both working memory and planning and it develops at the same time with the others. However, higher cognitive functions such as language and intelligence continue to develop into the third decade of life. In summary, these functions develop gradually, between 5 and 10 years of age, to reach completion at about age 12.

In the future, longitudinal studies will be required to verify our understanding of cognitive development. With the structural and functional neuroimaging studies, we are now in the position to concurrently track the development of neural systems and cognitive functioning, greatly enhancing our understanding of brain-behavior relationships.

It is known that abnormalities of PFC is associated with many of psychiatric disorders such as attention deficit and hyperactivity disorder, schizophrenia, obsessive compulsive disorder, depression, autism, etc. As we know more about the prefrontal cortex, we think that we could better understand these psychiatric disorders and could develop new treatment options.
