The human brain is by far the most complex organ in our body. Its cellular architecture and organization into neural networks enable such sophisticated functions as language, memory and abstract decision-making. But that very complexity comes at a cost: brain tissue has a very limited capacity for regeneration. Unlike skin or liver, neurons that die are rarely replaced. 

Rehabilitation helps restore some function, but in many cases, patients live with permanent motor and cognitive limitations. In addition, after a stroke, the risk of depression, dementia and other neurodegenerative diseases increases. However, this could soon change thanks to the development of stem cell-based therapies. 

This article was originally published in The Conversation