it's actually not too bad. There is a small micro electrode that is sub-millimeter, and the DBS electrode itself is ~1-1.5 mm depending on the model. The one

it's actually not too bad. There is a small micro electrode that is sub-millimeter, and the DBS electrode itself is ~1-1.5 mm depending on the model. The one traumatic part of it is that some groups use a device popularized by some of the French groups that use a 5-microelectrode array for the mapping portion of the surgery, which has a 4x4 cross sectional spread. This probably pins and destroys a lot of the brain tissue in its path, but the people who use it claim it gives them "better spatial resolution" in the mapping recordings. Which doesn't apparently improve overall accuracy anyway, but some people are married to using that damn device. Most surgeons in the US use 1-3 single electrode passes sequentially, which is a lot better.