Scientists at the University of Cambridge have created miniature brain and spinal cord circuits in the lab that mimic the neural pathways responsible for movement. Using this advanced model, they discovered that damage to these connections, long considered permanent, may actually be reversible.

As the human body develops from embryo to fetus and eventually into infancy, nerve cells called neurons form networks that allow signals to travel between the brain and spinal cord. A crucial part of these cells is the axon, a long nerve fiber that carries information to other neurons and helps trigger muscle movement.

However, at some point during development, neurons in the central nervous system lose much of their ability to grow new axons. As a result, damage to the brain or spinal cord often becomes permanent, leading to severe disabilities such as paralysis or loss of hand function. This limited regenerative capacity is a major challenge in traumatic spinal cord injuries and neurological disorders including motor neurone disease and multiple sclerosis.