持续短阵快速脉冲刺激右侧后顶叶区对不同参考框架视空间注意的影响

关键词：后顶叶皮层  单侧空间忽略  自我为中心  物体为中心  视空间注意

Keywords:posterior parietal cortex  unilateral space neglect  egocentric  allocentric  visuospatial attention

摘要：

      摘要 目的：通过持续短阵快速脉冲（cTBS）刺激健康人的右后顶叶皮层区（PPC）和右前额叶背外侧（DLPFC区），研究自我为中心和物体为中心参考框架下视空间注意的加工特点，评估是否诱导出类忽略（neglect-like）现象。 方法：招募健康受试者27名，随机分为3组，采用单次连续短阵快速脉冲（cTBS）刺激右侧脑区的PPC区（PPC_cTBS组）和DLPFC区（DLPFC_cTBS组），以及伪刺激CZ点（伪刺激组）。利用E-prime软件对受试者进行cTBS刺激后的Wilson改良空间注意测试，记录反应正确率和反应时，反映空间注意能力；应用有效、无效、中性线索提示的反应时间差计算注意网络效率。 结果：①空间注意测试表现：在物体为中心的无效线索下PPC_cTBS正确率（87.50%）较其他组明显下降（P=0.04）。采用多因素方差分析提示干预脑区类型、线索类型、目标方位对各组的物体为中心注意反应时不存在显著的主效应（P>0.05）。其次，各组在自我为中心的注意表现的准确率无显著性差异（P=0.554），但PPC_cTBS（453.35±208.45ms）的总平均反应时显著高于Sham_cTBS（424.31±137.77ms，P=0.012）及DLPFC_cTBS（423.74±116.04ms，P=0.011），且PPC_cTBS的无效和中性线索的反应时均高于其他组。提示cTBS“虚拟抑制”右PPC脑区明显抑制了以自我为中心的视空间注意的反应速度。进一步对比不同目标方位，发现识别左侧目标的平均反应时PPC_cTBS＞DLPFC_cTBS＞sham_cTBS（P=0.019），识别右侧目标的反应时PPC_cTBS＞sham_cTBS＞DLPFC_cTBS（all P>0.05），提示cTBS_PPC在自我为中心的左右空间信息加工均受损，尤其是抑制左侧目标的识别响应速度。②组间比较注意网络效率分析，结果发现在allo-task注意定向网络、注意警觉网络、执行控制网络不存在显著主体内效应差异（P=0.351，P=0.315，P=0.664）。在ego-task仅注意定向网络存在显著主体内效应差异（P=0.0425），而注意警觉网络、执行控制网络不存在差异（P>0.05），提示cTBS“虚拟抑制”PPC显著降低受试者的注意定向效率，明显低于sham_cTBS（P=0.0147）和DLPFC_cTBS（P=0.0113），出现注意解脱困难。 结论：cTBS“虚拟抑制”右侧PPC脑区，产生自我为中心空间注意的“neglect-like”现象，提示右后顶叶皮层区与自我为中心的空间注意密切相关。

Abstract:

      Abstract Objective： To investigate the effect of visuospatial attention and whether it can be induced a phenomenon of neglect-like， when the posterior parietal cortex （PPC） and dorsolateral prefrontal cortex （DLPFC） in the right hemisphere was applied over theta burst transcranial magnetic stimulation (cTBS). Method： Twenty-seven healthy participants were recruited and randomly assigned into 3 groups receiving cTBS stimulation in the right brain region： Sham_cTBS group，PPC_cTBS group， and DLPFC_cTBS group. Using the E-prime software， Wilson's modified spatial attention test was carried out to reflect spatial attention ability through response accuracy and reaction time. And the efficiency of attention network for calculating the response time difference of effective， ineffective and neutral cues. Result： ①Spatial attention test performance： The correct rate of PPC_cTBS（87.50%） in allocentric invalid cues was significantly lower than that in other groups（P=0.04）. Multivariate analysis of variance showed that there were no significant main effects among intervention brain area， cue type and target orientation on the response time of allocentric attention in each group（P>0.05）. There was no significant difference in the accuracy of attention performance in the egocentric frame（Z=2.089，P=0.554）. In terms of reaction time，it is found that the total average reaction time of PPC_cTBS（453.35±208.45ms） is significantly higher than that of Sham_cTBS（424.31±137.77ms，P=0.012） and DLPFC_cTBS（423.74±116.04ms，P=0.011）. In addition，the response time of PPC_cTBS was higher than that of other groups. In different target orientation analysis，it was found that the average response time of PPC_cTBS in recognizing left target was significantly higher than that of sham_cTB group（P=0.019）：PPC_cTBS>DLPFC_cTBS>sham_cTBS，PPC_cTBS is significantly higher than DLPFC_cTBS and sham_cTBS in identifying the right target： PPC_cTBS>sham_cTBS>DLPFC_cTBS， there is no significant difference in the rest（all P>0.05）. ② Attention network efficiency analysis showed that there was no significant intra-agent effect difference among allo-task attention-directed network， attention-alert network， and executive control network（P=0.351，P=0.315，P=0.664）. In ego-task， there were significant intra-subject effects differences only in attention orientation network（P=0.0425），but no differences in attention vigilance network and executive control network（P>0.05），suggesting that cTBS "virtual inhibition" of PPC significantly reduced the attention orientation efficiency of subjects. It is significantly lower than sham_cTBS（P=0.0147） and DLPFC_cTBS（P=0.0113）. Conclusion： The cTBS-induced "virtually inhibited" over the right PPC brain region could induce the phenomenon of "neglect-like" occurs， suggesting that the right posterior parietal cortex is closely related to egocentric spatial attention.