**Human mini-brains have taken root in the rat visual cortex and responded to flashing lights. Human neurons also responded to the orientation of lines** [Structural and functional integration of human forebrain organoids with the injured adult rat visual system](https://www.cell.com/cell-stem-cell/fulltext/S1934-5909(23)00004-8) Scientists are trying to find ways to repair the brain using tiny versions of it made from special cells. These "brain organoids" can grow into a shape that looks like the brain and have the potential to be a perfect match for patients in need of repair. However, it is not clear yet if these brain organoids can work with a damaged brain in a real animal. In a recent study, scientists showed that brain organoids can integrate and work with the visual system in a rat's brain after being transplanted into a damaged area. They found that the brain organoids and the rat's brain can communicate with each other, and the organoids can even respond to visual stimulation. This shows that brain organoids have the potential to restore brain function after damage, which is a promising step towards helping people with brain injuries. WDYT, @mr27.near?