Department of Psychology, University of Milano-Bicocca, Piazza dell'Ateneo Nuovo 1, 20126 Milan, Italy.
Neuropsychologia. 2011 Jul;49(9):2711-7. doi: 10.1016/j.neuropsychologia.2011.05.019. Epub 2011 Jun 12.
It is well known that viewing graspable tools (but not other objects) activates motor-related brain regions, but the time course of affordance processing has remained relatively unexplored. In this study, EEG was continuously recorded from 128 scalp sites in 15 right-handed university students while they received stimuli in the form of 150 pictures of familiar non-tool objects and 150 pictures of manipulable tools, matched for size, luminance and perceptual familiarity. To select the 300 images for the study, a wider set of preliminary stimuli was screened for motoric content by 20 judges using a 3-point scale (0=absent; 2=strong); pictures that scored below 1.5 or above 0.6 were excluded from the tool and non-tool categories, respectively. Tools and non-tools were presented in random order, interspersed with 25 photos of live plants. Each slide was presented for 1000 ms, with an interval ranging from 1500 to 1900 ms. The task consisted of responding to the photos of plants while ignoring the other stimuli. Both an anterior negativity (210-270 ms) and a centroparietal P300 (550-600 ms) were larger in response to tools than objects, particularly in the left hemisphere. swLORETA inverse solution identified the occipito-temporal cortex (BA19 and BA37) as the most significant source of activity (in the 210-270-ms time window) for both types of visual objects and the left postcentral gyrus (BA3) and the left and right premotor cortex (BA6) as the most significant source of activity for tools only. These data hint at an automatic access to motoric object properties even under conditions in which attention is devoted to other stimulus categories.
众所周知，观看可抓握工具（但不是其他物体）会激活与运动相关的大脑区域，但工具感知的时间进程仍然相对未知。在这项研究中，15 名右利手大学生连续 128 个头皮部位的 EEG 记录，同时他们接受了 150 张熟悉的非工具物体和 150 张可操作工具的图片刺激，这些图片在大小、亮度和感知熟悉度上相匹配。为了选择 300 张图片进行研究，一组更广泛的初步刺激物由 20 名评委使用 3 分制（0=不存在；2=强烈）进行运动内容筛选；评分低于 1.5 或高于 0.6 的图片分别被排除在工具和非工具类别之外。工具和非工具以随机顺序呈现，穿插着 25 张活体植物的照片。每张幻灯片呈现 1000ms，间隔在 1500 到 1900ms 之间。任务是在忽略其他刺激的情况下对植物的照片做出反应。与物体相比，对工具的反应在前额负（210-270ms）和中央顶 P300（550-600ms）都更大，特别是在左半球。swLORETA 逆解确定了枕颞皮质（BA19 和 BA37）是两种视觉物体活动（在 210-270ms 的时间窗口内）的最显著来源，左中央后回（BA3）和左、右运动前皮质（BA6）是工具活动的最显著来源。这些数据表明，即使在注意力集中在其他刺激类别的情况下，也可以自动访问运动物体属性。
