The brain can compensate for injury through optimization, potentially at a synaptic level.

“and and again parkinson's disease remember i mean that think about that model itself there's a threshold there i mean i've lost you know 40 of cells before i i i'm sure in functional impairment right so that's important because it gives us an idea that the brain may be able to tolerate some level of injury if you will and and through optimization you know which we still believe has to happen at a synaptic level because behavior is synaptic so to get functional improvement behavior you need something at a circuit level right right”