A group of researchers in La Jolla, California, have produced three-dimensional cerebral organoids (“mini-brains”) from human embryonic stem cells, later comparing the functionality of the tissue produced with samples of brain tissue from human fetuses with the same degree of development (see HERE). They also showed that the organoids produced have many of the epigenetic characteristics of human brains of a similar age. This is undoubtedly a major step for the study of brain function, but which has ethical difficulties, since human embryonic stem cells were used to produce the “mini-brains”; moreover, brain tissue — also from human fetuses — were used as control material.
Damaged brain tissue or spinal cord
Brain organoids are delicate organ structures derived from human stem cells, and certainly represent a great advance for the study of neuroscience. It is even thought that some of them may be an essential tool for replacing damaged brain tissue or spinal cord. So far, brain organoids appear to lack sufficient organization and structure so that they can not develop complex brain functions, although achieving this goal in the not-too-distant future cannot be ruled out.
Read a related article about bioethical problems that would have to be resolved as biological objectives are accomplished.