单脉冲经颅磁刺激对视皮层神经活动抑制作用的初步实验研究

为了研究单脉冲经颅磁刺激(sTMS)对视皮层神经活动的影响,利用多通道生理记录仪,分别记录下11名右利手志愿者sTMS作用于视皮层前后的视觉诱发电位(VEP)。采用叠加平均和巴特沃斯低通滤波的方法处理后,对比分析这两种情况下的VEP峰时特征,发现sTMS刺激将引起VEP峰值发生的时间有一定延迟。初步的实验结果表明,sTMS对视皮层神经活动有抑制作用,从而引起VEP产生了滞后,为将经颅磁刺激应用于研究视觉中枢神经活动提供了实验证据。     

棋盘格翻转的视野刺激区域对硬脑膜上皮质脑电的影响

To explore the effect of the location of a visual stimulus on neural responses in the primary visual cortex (V1), a micro-electromechanical system-based microelectrode array with nine channels was implanted on the cerebral dura mater of V1 in adult cats. 2 Hz pattern reversal checkerboard stimuli were used to stimulate the four visual quadrants (i.e., upper left, upper right, lower left, and lower right fields). The results showed that there was a N75 component of the visual evoked potential around 50-80 ms after the onset of a checkerboard stimulus, and the onset of these N75 peaks varied with different stimulus locations. The checkerboard stimuli induced shorter latencies in the contralateral V1 than in the ipsilateral V1, while the checkerboard stimulus in the upper half visual field induced shorter latencies for N75. These results suggested that the pattern-reversal stimuli induced neural activities in V1 that can be recorded with multichannel microelectrodes, and more detailed temporal and spatial properties can be measured.     

硬脑膜上微电极植入并记录家猫视皮层电活动

目的 建立初级视皮层区硬脑膜上柔性微电极阵列记录视皮层电活动的方法,比较黑白棋盘格图形和黑白闪烁刺激在诱发视觉诱发电位(visual evoked potential,VEP)方面的差异.方法 成年健康家猫5只,静脉持续麻醉,肌松、呼吸机人工通气,采用自行设计的柔性微电极阵列,微创植入并固定于视皮层定位区的硬脑膜上.比较无视觉刺激和有视觉刺激的视皮层电活动,验证是否能记录到VEP;给予闪光和图形视觉刺激,记录和比较视觉诱发电位的峰值和潜伏期.结果 通过微创手术将微电极阵列植入并固定在视皮层定位区的硬脑膜外;在硬脑膜外微电极阵列可记录到有效VEP;黑白棋盘格图形刺激与黑白闪烁刺激相比,前者诱发的VEP谷峰值显著高于后者(P<0.01),而诱发的VEP波谷潜伏期较后者长(P<0.05),且波峰潜伏期则显著长于后者(P<0.01).结论 在视皮层定位区硬脑膜外首创的微创植入并固定柔性微电极阵列的方法 适用性、重复性好,黑白棋盘格图形刺激优于黑白闪烁刺激,经硬脑膜外利用微电极阵列记录诱发电位是可行的.