Stanford Grows Human Brain Tissue Inside Mice in Science Breakthrough

Stanford scientists created mice with about 92% of cortical space occupied by human neural tissue from organoids. The model will allow testing psychiatric drugs on living human tissue; no signs of human consciousness were found.

• Human tissue occupied about 92% of cortex and grew 4.7x in 2–3 months
• Organoids implanted into mice aged 5–17 days
• Human cells formed connections with mouse brain and spinal cord
• Ethicists found no signs of human consciousness but note regulatory gaps