Traditionally, research on neurodegenerative diseases using human cells has primarily relied on the application of human-induced pluripotent stem (iPS) cells-derived neural cells. However, since neurodegenerative diseases typically manifest in older individuals, studies using human iPS cells, which reset cellular age to zero, have inherent limitations. To overcome these challenges, a new approach has emerged: directly induced neurons (iNs), which are converted directly from somatic cells. This paper provides an overview of how these cells are induced and their applications in studying various diseases.