Neurons from stem cells replace damaged neurons and integrate into the brain, by NextBigFuture. More research on this, please.

[R]esearchers have found that transplanted embryonic nerve cells properly differentiated into pyramidal cells, forming normal synaptic connections, responding to visual stimuli, and carrying out the tasks performed by the damaged cells (videos here).

The researchers were also “astounded” to find that the replacement neurons grew axons throughout the adult brain, reaching proper target areas, and receiving V1-specific (from the primary visual cortex) inputs from host neurons — precisely the same inputs that the original neurons had received.

hat-tip Matthew