Nir Grossman, David Bono, Nina Dedic, Suhasa B. Kodandaramaiah, Andrii Rudenko, Ho-Jun Suk, Antonino M. Cassara, Esra Neufeld, Niels Kuster, Li-Huei Tsai, Alvaro Pascual-Leone, and Edward S. Boyden, Cell, , Issue 6, pp. 1029–1041, online 1 June 2017, doi: 10.1016/j.cell.2017.05.024
The paper reports a noninvasive strategy for electrically stimulating neurons at depth. By delivering to the brain multiple electric fields at frequencies too high to recruit neural firing, but which differ by a frequency within the dynamic range of neural firing, it is possible to electrically stimulate neurons throughout a region where interference between the multiple fields results in a prominent electric field envelope modulated at the difference frequency. This temporal interference (TI) concept was validated via modeling and physics experiments, and it was verified that neurons in the living mouse brain could follow the electric field envelope. The utility of TI stimulation is demonstrated by stimulating neurons in the hippocampus of living mice without recruiting neurons of the overlying cortex. Finally, it is shown that by altering the currents delivered to a set of immobile electrodes, different motor patterns can be steerably evoked in living mice.
The scientific and technical impact of the study can be summarized as:
- A new, noninvasive technique to stimulate deep brain structures has been developed and tested by using computational modeling and phantom measurements, as well as electrophysiological measurements in vivo;
- TI stimulation sends interfering, low-frequency modulated, high frequency signals from multiple pairs of electrodes placed on the scalp through the brain, avoiding stimulation of other areas;
- The results make TI stimulation a promising alternative to surgical electrical stimulation interventions such as deep brain stimulation (DBS) for e.g., Parkinson's disease patients.