The brain of a person with Parkinson's disease works like an orchestra where the conductor either freezes or waves the baton off-beat. Medications don't help everyone, so doctors turn to stimulation — weak electrical pulses that restore the rhythm. But each brain is wired differently: one person responds to one approach, another to the second. Getting it wrong means operating on someone for nothing.
Scientists built a virtual copy of the brain. They trained it on thousands of scans so it could recognize what the disease looks like. Then they tailored the copy to each of the 106 patients who underwent stimulation. The copy is so accurate that it replicates real brain connections with 93.5% agreement. Next, they compared the diseased brain and the healthy one in this copy, like showing the same garden before and after a drought. Based on the difference, the model predicted whether stimulation would help that person.
Testing on new patients confirmed the method is ready for the clinic. What's more, the model revealed which brain regions matter for successful treatment. That gives doctors a hint about where to direct stimulation. In this way, the virtual brain becomes a rehearsal before the real surgery.
The model's prediction accuracy is comparable to that of an experienced doctor who has observed patients for years.
The idea of a virtual brain twin echoes the 'surrogates' from the movie of the same name, where a person controls a perfect copy of themselves without leaving home.