Figure 2.

Timeline of key findings in current brain organoid research. Research on organoids began with two studies. Organotypic, a culture method that divides organs or tissues into smaller units and then re-builds them in vitro, has long been used for the external growth of tissues. This figure illustrates the presence of adult stem cells in different organs, leading to adult stem cell-based organoid study. On a separate note, the basis for the study of brain organoids has been the plethora of studies of self-organizing pluripotent stem cells. Nowadays, research on brain organoids has surpassed the stage of creating region-specific organoids to better mimic the in vivo brain properties, such as vascularization and axis formation.