A new type of noninvasive brain stimulation that makes use of pulsed ultrasound can stimulate nerves via electrical stimulation. This sort of success in the use of pulsed ultrasound lends hope that noninvasive brain stimulation will be ultimately be a significant treatment for injuries and disease and may even be used in the future for enhancing cognitive abilities.
Pulsed ultrasound activates brain waves called sharp-wave ripples in the hippocampus. Sharp-wave ripples are linked to the forming of memories. Pulsed ultrasound also triggered production of neurotrophic factor (BENF) which influences brain plasticity.
Research was led by neuroscientist William "Jamie" Tyler, with a scientific team at Arizona State University. "Tyler believes that there are a host of potential applications for ultrasound in brain manipulation. Besides basic science and medical uses, ultrasound represents a core platform around which future brain-machine interfaces can also be designed for gaming, entertainment and communication purposes because of its noninvasive nature."
http://www.sciencedaily.com/releases/2010/06/100609122832.htm