Research On Key Issues In Transcranial Focused Ultrasound Neuromodulation Technology

Neuromodulation technology has been widely used in the research and treatment of mental disorders,functional brain diseases,addictions,and functional recovery after nervous system damage.In many in-vivo and ex-vivo animal models and even the human brain,low-intensity focused ultrasound is the only non-invasive neuromodulation technology that can reach the deep brain with high spatiotemporal resolution,and has great potential in basic research and clinical applications of the nervous system.At present,a number of studies on ultrasonic neural regulation have proved its ability to effectively regulate neural activities in the brain.However,due to the attenuation and phase distortion of ultrasonic signals caused by the skull,it is difficult for the ultrasonic signals to accurately focus in the brain after passing through the skull.More importantly,the current studies on ultrasonic neural regulation are based on the results of stimulation to feedback the effectiveness of regulation.There is no actual tool to prove the location of focusing target in the brain,but in neural regulation,the accuracy of focusing target determines the regulation effect and experimental conclusion.In order to solve the precise focusing of low-intensity ultrasound in the brain,this research has done the following work: 1.The traditional single channel ultrasonic neural regulation equipment is improved to achieve magnetic resonance compatibility;2.The influence of skull on ultrasound was simulation designed and tested;3.The magnetic resonance acoustic radiation force technology was introduced to make the ultrasound focusing under the guidance of magnetic resonance more accurate,and then to carry out neuromodulation work under the mental image representation（magnetic resonance imaging）.In conclusion,through the above three works,thesis proposes a new solution to the target focusing problem in MRI-compatible ultrasound neuromodulation technology.Simulation and experiments have proved that this scheme can indeed be used to determine the focal position of low-intensity transcranial ultrasound,which lays a foundation for further in-depth research on the mechanism of ultrasound neuromodulation and clinical application.