Jay Sanguinetti in Tucson, U of A, is doing some really awesome stuff with Ultrasound and the brain. Anyone interested should take a look at his research,
https://www.jaysanguinetti.com/transcranial-ultrasound
https://www.youtube.com/watch?v=rGEjmwaIPZk&feature=emb_logo
Ted talk - A Technoboost for Meditation