Abstract

Mechanisms of Stimulation Effects of Focused Ultrasound on Neural Structures: Role of Nonlinear Effects

L.R.Gavrilov (N.N. Andreyev Acoustics Institute, Moscow, Russia); E.M.Tsirulnikov (Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, St.Petersburg, Russia)

e-mail: bvp@akin.ru

The feasibility of the use of short pulses of focused ultrasound for noninvasive local stimulation of superficial and deep-seated neural structures of humans to induce different somatic (tactile, warmth, cold, pain, etc.), hearing and other sensations is discussed. Such possibilities are of interest for the application of this method in physiology and clinical practice, e.g., for diagnosis of neurological, dermatological, hearing and other diseases involving changes in perception of different sensations. It is evident that a better understanding of the mechanisms underlying the stimulation effects of focused ultrasound is very important for effective and safe applications of this method. We have tried to reveal the main factor(s) responsible for the stimulation effects of focused ultrasound. Experimental observations show that the temperature factor should be excluded from the consideration and it is necessary to search the main effective factors amongst the mechanical ones. It is evident also that the actual mechanism of the ultrasound stimulation of neural structures should be related to a certain "unidirectional", "rectified" action rather than to a sign-altering oscillations of the medium. The role of nonlinear effects in the possible mechanisms of stimulation effects of focused ultrasound on human neural structures is discussed.

Section : 5