Department of Psychology, University of Auckland, Auckland, New Zealand.
Neuropsychologia. 2011 Nov;49(13):3758-67. doi: 10.1016/j.neuropsychologia.2011.09.034. Epub 2011 Sep 28.
High-density ERPs evoked by rotated alphanumeric characters were examined to determine how neural processing is affected by stimulus orientation during letter/digit classifications and during mirror/normal discriminations. The former task typically produces response times that are unaffected by stimulus orientation while the latter is thought to require mental rotation. Sensitivity to orientation was first observed around 100-140 ms and this effect was attributed to differences in low-level features between vertical and oblique orientations. Subsequently, character misorientation amplified the N170, a neural marker of object classification, between 160 and 220 ms. Top-down processing is reflected in the ERPs beginning at 280-320 ms and this time range may reflect binding of ventral and dorsal stream information. In the case of mirror-normal discrimination these top-down processes can lead to mental rotation between 340 and 700 ms. Therefore, although neural processing reflects object orientation, these effects do not translate into increases in reaction-times or impaired accuracy for categorisation, and precede those that do in the mental-rotation task.
研究了由旋转的字母数字字符引发的高密度 ERP，以确定在字母/数字分类和镜像/正常辨别过程中，刺激方向如何影响神经处理。前者通常产生不受刺激方向影响的反应时间，而后者则被认为需要心理旋转。大约在 100-140ms 左右首次观察到对方向的敏感性，这种效应归因于垂直和倾斜方向之间的低水平特征差异。随后，字符错误方向在 160 到 220ms 之间放大了 N170，这是对象分类的神经标志物。自上而下的处理反映在 280-320ms 开始的 ERP 中，这个时间范围可能反映了腹侧和背侧流信息的绑定。在镜像-正常辨别中，这些自上而下的过程可以在 340 到 700ms 之间导致心理旋转。因此，尽管神经处理反映了物体的方向，但这些影响不会导致反应时间增加或分类准确性下降，并且先于心理旋转任务中的那些影响。
