RESUMEN
BACKGROUND:Transcranial magneto-acoustical electrical stimulation(TMAES)is a non-invasive,high-precision neurofocused stimulation method based on magneto-acoustic coupling electrical effect,which can regulate the rhythmic oscillation of nerve activity,thereby affecting the brain's movement,cognition and other functions. OBJECTIVE:To explore the effect of TMAES on beta oscillations in the neural circuits of healthy rats and Parkinson's rats. METHODS:(1)Animal experiments:Twenty-four Wistar rats were randomly divided into four groups(n=6 per group).The rats in the normal control group received no intervention,while those in the normal stimulation group received TMAES(the average spatial peak pulse intensity:13.33 W/cm2,fundamental frequency:0.4 MHz,the number of fundamental wave cycles:1000,and pulse frequency:200 Hz).The model control group and model stimulation group were established by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine.After successful modeling,the rats in the model control group received sham TMAES stimulation in the prefrontal cortex,and those in the model stimulation group received TMAES in the prefrontal cortex,and the duration of stimulation was 2.0 minutes per day.After an interval of 8-10 minutes,the local field potential signals of rats were collected during the execution of T-maze test and the correct rate of behavior was recorded at the same time to compare and analyze the time-frequency distribution of local field potential signals and behavioral differences among the groups.The stimulation experiment and T-maze test were stopped when the correct rate of rats was higher than 80%for 3 consecutive days.(2)Modeling and simulation experiments:The cortical-basal ganglion circuit model under TMAES was established,and the ultrasonic emission period(5,10,20 ms),ultrasonic emission duty cycle(30%,50%,90%)and induced current density(20,50,100 μA/cm2)were changed respectively to compare the power spectral density values of beta oscillations in healthy rats and Parkinson's rats under different stimulation parameters. RESULTS AND CONCLUSION:(1)Animal experiments:The spatial learning ability of the rats in the normal control group was stronger than that of the model control group(P＜0.001),the spatial learning ability of the rats in the normal stimulation group was stronger than that of the normal control group(P＜0.05),and the spatial learning ability of the rats in the model stimulation group was stronger than that of the model control group(P＜0.01).The distribution of beta oscillation energy in the normal control group was more concentrated,and the beta oscillation signal energy was reduced in the normal stimulation group compared with the normal control group.The beta oscillation energy was widely distributed and the energy value was significantly higher in the model control group and the model stimulation group than the normal control and normal stimulation groups.Moreover,the beta oscillation signal energy in the model stimulation group was significantly lower than that in the model control group.(2)Modeling and simulation experiments:the peak power spectral density of the beta band of healthy rats without stimulation(30 dB)was significantly lower than that of Parkinson's rats(55 dB).The power spectral density value generally decreased after stimulation.The peak power spectral density in the beta band was positively correlated with the ultrasonic emission period and negatively correlated with the induced current density.In addition,the peak power spectral density value was the lowest when the duty cycle of ultrasonic emission was 50%.These findings indicate that TMAES suppresses beta oscillations in healthy and Parkinson's disease rats,thereby improving motor function and decision-making cognitive function in rats.
RESUMEN
Transcranial magneto-acoustic-electrical stimulation is a new non-invasive neuromodulation technology, in which the induced electric field generated by the coupling effect of ultrasound and static magnetic field are used to regulate the neural rhythm oscillation activity in the corresponding brain region. The purpose of this paper is to investigate the effects of transcranial magneto-acoustic-electrical stimulation on the information transfer and communication in neuronal clusters during memory. In the experiment, twenty healthy adult Wistar rats were randomly divided into a control group (five rats) and stimulation groups (fifteen rats). Transcranial magneto-acoustic-electrical stimulation of 0.05~0.15 T and 2.66~13.33 W/cm 2 was applied to the rats in stimulation groups, and no stimulation was applied to the rats in the control group. The local field potentials signals in the prefrontal cortex of rats during the T-maze working memory tasks were acquired. Then the coupling differences between delta rhythm phase, theta rhythm phase and gamma rhythm amplitude of rats in different parameter stimulation groups and control group were compared. The experimental results showed that the coupling intensity of delta and gamma rhythm in stimulation groups was significantly lower than that in the control group ( P<0.05), while the coupling intensity of theta and gamma rhythm was significantly higher than that in the control group ( P<0.05). With the increase of stimulation parameters, the degree of coupling between delta and gamma rhythm showed a decreasing trend, while the degree of coupling between theta and gamma rhythm tended to increase. The preliminary results of this paper indicated that transcranial magneto-acoustic-electrical stimulation inhibited delta rhythmic neuronal activity and enhanced the oscillation of theta and gamma rhythm in the prefrontal cortex, thus promoted the exchange and transmission of information between neuronal clusters in different spatial scales. This lays the foundation for further exploring the mechanism of transcranial magneto-acoustic-electrical stimulation in regulating brain memory function.