I don't think that's physically possible. It could shrink some, it could be surgically removed, it could be sucked out by alien beings but the cerebral cortex would not simply dissolve into nothingness.
If you wish to keep promoting what appears to be nothing more than a canard show us in some sound medical literature that brain tissue can disappear. Then show us Terri's brian scan not one of Felos' liar-for-hire's reports. Then tell us what difference the brain scan makes when the subject in question obviously tries very hard to respond to people and things around her.