Multi-channel magnetic stimulation is an efficient method to improve the conventional magnetic stimulation. A multi-channel magnetic brain stimulator was developed and the distribution of magnetic field was calculated by finite-element analysis software-ANSYS. The results show that when five coils work simultaneously, the area where the magnetic flux density is larger than 0.01 T would expand to almost the whole brain region, and the magnetic stimulation depth would be improved. Experiments were performed on ten subjects (mean age 25) using the stimulator, and the EEG power spectrums before and after stimulation were analyzed. The experimental results show that the beta component of EEG obviously increases after magnetic stimulation, and the effect is more obvious by using more coils simultaneously because of the deeper stimulation.
本研究目的是确定人兴奋时的脑波特征及兴奋发生源在脑区的解剖位置,通过饮用定量的咖啡使人摄入咖啡因形成兴奋,同时用128导联数字脑电系统采集EEG(E lectroencepha logram)信号,与未饮用咖啡之前的安静状态的EEG信号进行功率谱比对。发现两者之间有明显的区别,表现出人在兴奋时的脑波特征是10 H z以下的低频成分受到明显抑制,同时高频处产生一个38 H z的波峰,高度在200左右。利用A SA源分析软件对兴奋的发生源区域进行定位,发现兴奋的发生区域集中在脑桥腹侧正中下部的区域。
