Castelli Fulvia, Glaser Daniel E, Butterworth Brian
Division of the Humanities and Social Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
Proc Natl Acad Sci U S A. 2006 Mar 21;103(12):4693-8. doi: 10.1073/pnas.0600444103. Epub 2006 Mar 14.
The human intraparietal sulcus (IPS) is implicated in processing symbolic number information and possibly in nonsymbolic number information. Specific IPS activity for discrete quantities (numerosities) as compared with continuous, analogue quantity has not been demonstrated. Here we use a stimulus-driven paradigm to distinguish automatic estimation of "how many things" from "how much" and "how long." The discrete analogue response task (DART) uses the perception of hues which can change either abruptly (discrete, numerous stimuli) or smoothly (analogue, nonnumerous stimuli) in space or in time. Subjects decide whether they saw more green or more blue. A conjunction analysis of spatial and temporal conditions revealed that bilateral IPS was significantly more active during the processing of discrete stimuli than during analogue stimuli, as was a parietal-occipital transition zone. We suggest that processing numerosity is a distinct process from processing analogue quantity, whether extended in space or time, and that an intraparietal network connects objects' segmentation to the estimation of their numerosity.
人类顶内沟（IPS）与处理符号数字信息有关，可能也与非符号数字信息有关。与连续的、类似数量相比，尚未证明IPS对离散数量（数字）有特定的活动。在这里，我们使用一种刺激驱动范式来区分对“有多少事物”与“有多少”和“有多长”的自动估计。离散类似物反应任务（DART）利用对色调的感知，色调在空间或时间上可以突然变化（离散的、众多的刺激）或平滑变化（类似物、非众多的刺激）。受试者判断他们看到的绿色多还是蓝色多。对空间和时间条件的联合分析表明，双侧IPS在处理离散刺激时比处理类似物刺激时显著更活跃，顶枕过渡区也是如此。我们认为，处理数字是一个与处理类似数量不同的过程，无论其在空间还是时间上的延伸，并且顶内网络将物体的分割与对其数量的估计联系起来。
