The Transplanted Brain | BBC Documentary | Horizon

One of the most significant barriers to the procedure is the inability of nerve tissue to heal properly; scarred nerve tissue does not transmit signals well, which is why a spinal cord injury is so devastating. Alternatively, a brain–computer interface can be used connecting the subject to their own body. A study using a monkey as a subject shows that it is possible to directly use commands from the brain, bypass the spinal cord and enable hand function. An advantage is that this interface can be adjusted after the surgical interventions are done where nerves can not be reconnected without surgery. Also, for the procedure to be practical, the age of the donated body must be sufficient: an adult brain cannot fit into a skull that has not reached its full growth, which occurs at age 9–12 years. When organs are transplanted, aggressive rejection by the host’s immune system can occur. Because immune cells of the CNS contribute to the maintenance of neurogenesis and spatial learning abilities in adulthood, the bra