Circular RNAs in Brain Physiology and Disease.

Circular RNAs (circRNAs) are endogenously expressed non-coding RNAs discovered in the early 1990s as a transcriptional by-product of little importance. It was only recently that they were identified as a key player in regulating the gene expression by targeting and modulating the functions of microRNA, a process known as microRNA sponging. They are distributed throughout the system in a tissue-specific manner showing abundant enrichment in neuronal tissue. Their physiological functions in the brain such as neuronal maturation, differentiation, etc. as well as their implications in numerous brain-related disorders have made its entry into the spotlight. Yet the wider scope and molecular mechanism of circRNAs still remain elusive. In this chapter, we describe in detail the functional aspects and importance of circRNAs in the human brain and how it is associated with various neurological diseases.