Design And Application Of Transcranial Ultrasound Stimulation Navigation System

Transcranial focused ultrasound stimulation(t FUS)technology,is an emerging technology in the field of neuromodulation.It has several outstanding advantages,such as higher spatial resolution,deeper stimulation depth,non-invasiveness and magnetic resonance compatibility,compared with traditional techniques.Its high spatial resolution and precise stimulation require the support of the corresponding navigation system.However,the current t FUS still lacks of the navigation function module.Therefore,this thesis designed a software navigation system combined with t FUS hardware equipment.The system can track the position of the patient’s head and the ultrasonic transducer in real time,recording the position of the ultrasound focused stimulus and the spatial position of the transducer to achieve precise ultrasound stimulation.The navigation software system can also store and manage the experimental data and results,and support the transplantation and recording of different computer terminals.After the system had been successfully built,we applied the ultrasound navigation system to a visual selective spatial attention task.Using behavioral and EEG analyses,we aimed to test the neuromodulation of t FUS and verify the repeatability.The repeatability experiment requires that each experiment stimulates the same brain region,avoiding the focus displacement when the experiment is repeated.Therefore,t FUS must be navigated by a highprecision navigation system.We recruited four volunteers and applied inhibitory ultrasound stimulation to their prefrontal lobe.For each subject,three repetitive experiments were performed,with 1 week interval between two successive experiments.In each experiment,behavior and EEG signals were recorded under real stimulation and sham stimulation conditions.The results showed that the application of t FUS would significantly increase the response time,and reduced the laterality of the occipital α-power,indicating that transcranial inhibitory ultrasound stimulation of the prefrontal lobe have an inhibitory effect on the occipital region which is involved in visual spatial attention.The results demonstrated the neuromodulation effect of transcranial ultrasound stimulation.In addition,the inhibitory neuromodulation effect was similar in the three repetitive experiments,which suggested that the ultrasound navigation system we designed was effective,and the transcranial ultrasound focused stimulation experiment was reproducible.