The Study Of Cerebral Hemodynamics In Rats By Transcranial Direct Current And Ultrasonic Stimulation

At present,cerebrovascular disease has become one of the three major diseases,which has threatened the human health seriously.It accounts for about 32 percent of the global total disease burden,and also ranks first among the overall burden of disease in China.Effective control and treatment of cerebrovascular diseases can improve the health of our nation and reduce our medical expenditure.The treatment methods used commonly for cerebrovascular diseases are drug therapy and deep brain stimulation,but these treatments are injurious to human beings,with the disadvantages of side effects and insufficient spatial resolution.Transcranial direct-current stimulation(tDCS)and transcranial ultrasonic brain stimulation(TUS)offer a method for noninvasive neuromodulation usable in basic and clinical human neuroscience.Transcranial direct-current stimulation that utilizes weak currents to regulate the cerebral blood flow and the activity of neurons in the cerebral cortex.Transcranial ultrasonic brain stimulation(TUS)is a brain regulation technique that uses specific ultrasound to function in the cerebral blood flow and brain's nervous system.Transcranial direct current and ultrasonic brain stimulation has been a new method of brain regulation developed in recent years.The technique uses direct current and ultrasonic energy through a complete skull,which makes a biological mechanical effects on cerebral blood flow and brain neurons.Compared with traditional drug therapy and magnetic stimulation,it has the advantages of no damage,high penetration depth and high spatial resolution.In order to study the transcranial direct current and ultrasonic stimulation effect on cerebral blood flow furtherly,based on blood flow of the rats as the research object,we would discuss the changes of the cerebral blood flow under the transcranial direct current stimulation and ultrasonic.stimulationIn this paper,we first set up two experimental systems of transcranial direct current and ultrasound stimulation,and then we used the laser-speckle contrast imaging(LSCI)to study and analyze the hemodynamic response under the stimulation of transcranial direct current and ultrasonic.And the rats cerebral blood flow images were collected by themethod of laser speckle image reconstruction.Laser-speckle contrast imaging,a powerful,low-cost method for obtaining images of dynamic systems,can detect regional blood-flow distributions with high spatial and temporal resolutions.The functional activities and disease mechanisms of biological tissues can be demonstrated through the microcirculation of blood.So microcirculation blood flow monitoring is a very important medical diagnostic method.Finally,measuring the distribution of cerebral blood flow in rats with transcranial direct current and ultrasound,we obtained the change-rate of cerebral blood flow could reach approximately 10.1 ± 5.1% by DCS,and the change-rate of cerebral blood flow could reach approximately 115.1±6.5% by TUS,which indicates that tDCS and TUS can increase the cerebral blood flow and alter cortical hemodynamic responses.In addition to measure the change of blood flow velocity,we also measured the changes in blood vessel diameter in rats.We found that the rats blood vessel diameter increased under the effect of ultrasonic stimulation,which suggests that transcranial ultrasound can not only increase cerebral blood flow,but can also change the hemodynamic response of rat brain.Thus,tDCS and TUS will show potential for the clinical treatment and rehabilitation of ischemic strokes in the future.