In mammalian cells, transcription and gene expression are dynamically regulated by a variety of factors, and transcriptional controls are paramount for most genes. The central dogma of gene expression includes two main steps, namely, RNA transcription from the DNA sequence, followed by protein translation from the RNA sequence. Enhancer RNAs (eRNAs) are a class of long noncoding RNAs (lncRNAs) that are transcribed from DNA sequences upstream or downstream of active enhancer regions. In cortical neurons, eRNAs are synthesized in response to membrane depolarization, prior to the end of mRNA transcription. During neuronal development, various gene expression changes occur in the neurons, and such gene expression programs are necessary for synapse formation or maturation. Activity-regulated transcriptional programs are essential for the maturation or development of synapses, and transcription of gene contributes many cognitive disorders, which include Fragile X syndrome, Down syndrome, autism spectrum disorders or other rare genetic disorders. One interesting my preliminary data indicated that endogenous eRNAs altered mouse behavior, and completely impaired the fear memory. Altogether, these evidences could imply that not only endogenous eRNAs directly regulates specific gene expression but also could be alter behavior in vivo. Therefore, high target gene specificity eRNAs may be useful therapeutic or diagnosis targets, and unique biomarkers of various diseases.