A study published in *Nature* (476, 228–231, 2011) demonstrates that microRNAs (miRNAs) can convert human fibroblasts into neurons. The research shows that miR-9* and miR-124, when expressed in human fibroblasts, induce their transformation into neurons, a process facilitated by the transcription factor NEUROD2. The addition of neurogenic transcription factors ASCL1 and MYTIL enhances the conversion rate and maturation of the neurons. These miRNAs target genes involved in neuronal differentiation and function, and their combined action with NEUROD2 and other transcription factors leads to the formation of functional neurons. The converted neurons exhibit characteristics of post-mitotic neurons, including the expression of markers like MAP2, SCN1a, synapsin 1, and NMDAR1. Electrophysiological recordings show that these neurons can generate action potentials and exhibit voltage-gated sodium and potassium currents. Calcium imaging and FM1-43 imaging further confirm their ability to support activity-dependent calcium influx and synaptic function. The study also shows that the conversion can be achieved in adult fibroblasts, albeit more slowly. The findings suggest that miRNAs play an instructive role in neural fate determination by modulating chromatin remodeling complexes and gene expression. The research highlights the potential of miRNAs in inducing neural differentiation and provides insights into the genetic circuitry underlying neural development.A study published in *Nature* (476, 228–231, 2011) demonstrates that microRNAs (miRNAs) can convert human fibroblasts into neurons. The research shows that miR-9* and miR-124, when expressed in human fibroblasts, induce their transformation into neurons, a process facilitated by the transcription factor NEUROD2. The addition of neurogenic transcription factors ASCL1 and MYTIL enhances the conversion rate and maturation of the neurons. These miRNAs target genes involved in neuronal differentiation and function, and their combined action with NEUROD2 and other transcription factors leads to the formation of functional neurons. The converted neurons exhibit characteristics of post-mitotic neurons, including the expression of markers like MAP2, SCN1a, synapsin 1, and NMDAR1. Electrophysiological recordings show that these neurons can generate action potentials and exhibit voltage-gated sodium and potassium currents. Calcium imaging and FM1-43 imaging further confirm their ability to support activity-dependent calcium influx and synaptic function. The study also shows that the conversion can be achieved in adult fibroblasts, albeit more slowly. The findings suggest that miRNAs play an instructive role in neural fate determination by modulating chromatin remodeling complexes and gene expression. The research highlights the potential of miRNAs in inducing neural differentiation and provides insights into the genetic circuitry underlying neural development.