Leek E Charles, Roberts Mark V, Dundon Neil M, Pegna Alan J
School of Psychology, Institute of Life and Human Sciences, University of Liverpool, Liverpool, L69 7ZA, UK.
School of Psychology, Bangor University, Bangor, UK.
Eur J Neurosci. 2020 Dec;52(11):4453-4467. doi: 10.1111/ejn.14270. Epub 2018 Dec 26.
This study used event-related potentials (ERPs) to elucidate how the human visual system processes three-dimensional (3-D) object shape structure. In particular, we examined whether the perceptual mechanisms that support the analysis of 3-D shape are differentially sensitive to higher order surface and volumetric part structure. Observers performed a whole-part novel object matching task in which part stimuli comprised sub-regions of closed edge contour, surfaces or volumetric parts. Behavioural response latency data showed an advantage in matching surfaces and volumetric parts to whole objects over contours, but no difference between surfaces and volumes. ERPs were analysed using a convergence of approaches based on stimulus dependent amplitude modulations of evoked potentials, topographic segmentation, and spatial frequency oscillations. The results showed early differential perceptual processing of contours, surfaces, and volumetric part stimuli. This was first reliably observed over occipitoparietal electrodes during the N1 (140-200 ms) with a mean peak latency of 170 ms, and continued on subsequent P2 (220-260 ms) and N2 (260-320 ms) components. The differential sensitivity in perceptual processing during the N1 was accompanied by distinct microstate patterns that distinguished among contours, surfaces and volumes, and predominant theta band activity around 4-7 Hz over right occipitoparietal and orbitofrontal sites. These results provide the first evidence of early differential perceptual processing of higher order surface and volumetric shape structure within the first 200 ms of stimulus processing. The findings challenge theoretical models of object recognition that do not attribute functional significance to surface and volumetric object structure during visual perception.
本研究使用事件相关电位（ERP）来阐明人类视觉系统如何处理三维（3-D）物体形状结构。具体而言，我们研究了支持3-D形状分析的感知机制是否对高阶表面和体积部分结构具有不同的敏感性。观察者执行了一项整体-部分新颖物体匹配任务，其中部分刺激包括封闭边缘轮廓、表面或体积部分的子区域。行为反应潜伏期数据显示，将表面和体积部分与整个物体进行匹配时比轮廓具有优势，但表面和体积之间没有差异。使用基于诱发电位的刺激依赖性幅度调制、地形分割和空间频率振荡的多种方法对ERP进行分析。结果显示了对轮廓、表面和体积部分刺激的早期差异感知处理。这首先在N1（140 - 200毫秒）期间在枕顶叶电极上可靠地观察到，平均峰值潜伏期为170毫秒，并在随后的P2（220 - 260毫秒）和N2（260 - 320毫秒）成分上持续存在。N1期间感知处理中的差异敏感性伴随着区分轮廓、表面和体积的独特微状态模式，以及右枕顶叶和眶额部位约4 - 7赫兹的主要θ波段活动。这些结果提供了在刺激处理的前200毫秒内对高阶表面和体积形状结构进行早期差异感知处理的首个证据。这些发现挑战了在视觉感知过程中不赋予表面和体积物体结构功能意义的物体识别理论模型。
