Adam J J, Bovend'Eerdt T J H, Schuhmann Teresa, Sack A T
Faculty of Health, Medicine and Life Sciences, Maastricht University, The Netherlands.
Faculty of Health, Medicine and Life Sciences, Maastricht University, The Netherlands.
Behav Brain Res. 2016 Mar 1;300:143-9. doi: 10.1016/j.bbr.2015.12.018. Epub 2015 Dec 14.
Recent evidence has revealed an advantage for movements to last target positions in a structured visual display, suggesting a mediating role of allocentric, in addition to egocentric, information in goal-directed reaching. This notion is accommodated by the recently updated perception-action model (Milner and Goodale, 2008), which postulates functional roles of ventral and dorsal neural areas in allocentric coding. In the present study, we used imaging-guided multi-site continuous theta burst stimulation (cTBS) over regions of the ventral and dorsal processing streams to unravel their functional contribution on visually guided reaching in two display conditions: the "egocentric" condition where the target appeared in an empty display and the "allocentric" condition where the target appeared in a structured display with placeholders marking possible target locations. Cortical sites for cTBS were identified individually for each participant via coregistration with magnetic resonance scans. Results indicated that cTBS in the egocentric condition did not affect movement time, but cTBS in the allocentric condition modulated movement time contingent on stimulation site and target position. In particular, cTBS over the lateral occipital cortex (part of the ventral stream) and over the angular gyrus (part of the dorsal stream) eliminated the last-target advantage by slowing down reaching to the salient last target position. cTBS over the superior parietal occipital cortex did not affect the last-target advantage. These outcomes provide the first causal evidence for allocentric coding in ventral and dorsal routes during real-time reaching, thereby supporting the updated perception-action model.
最近的证据显示，在结构化视觉显示中，向最终目标位置的运动具有优势，这表明在目标导向的伸手动作中，除了自我中心信息外，异我中心信息也起到了中介作用。最近更新的感知-动作模型（米尔纳和古德尔，2008年）认可了这一观点，该模型假定腹侧和背侧神经区域在异我中心编码中具有功能作用。在本研究中，我们使用成像引导的多部位连续theta爆发刺激（cTBS），作用于腹侧和背侧处理流区域，以揭示它们在两种显示条件下对视觉引导伸手动作的功能贡献：“自我中心”条件下，目标出现在空白显示中；“异我中心”条件下，目标出现在带有标记可能目标位置的占位符的结构化显示中。通过与磁共振扫描进行配准，为每个参与者单独确定cTBS的皮质部位。结果表明，自我中心条件下的cTBS不影响运动时间，但异我中心条件下的cTBS根据刺激部位和目标位置调节运动时间。特别是，枕外侧皮质（腹侧流的一部分）和角回（背侧流的一部分）上的cTBS通过减慢伸向突出的最终目标位置的速度，消除了最终目标优势。顶上枕叶皮质上的cTBS不影响最终目标优势。这些结果为实时伸手过程中腹侧和背侧路径中的异我中心编码提供了首个因果证据，从而支持了更新后的感知-动作模型。
