Neurons—the nerve cells responsible for transmitting electrical and chemical signals throughout the body—are organized in tissue, tending to cluster together in groups according to how they function.

Adaptive deep brain stimulation was approved earlier this year by the US and European health authorities. It involves a computer interpreting brain activity and deciding whether to adjust the ...

In the case of Parkinson’s, stimulation effects are almost immediate, so it is relatively easy to see how well particular ...