Prior work has shown that the lateral occipital cortex (LO) is involved in recognition of objects and their parts, as well as segregation of that object (or “figure”) from its background. No studies, though, have examined how LO's functioning is influenced by non-invasive brain stimulation, particularly during a figure-ground perception task. The present study tested whether high-definition transcranial direct current stimulation (HD-tDCS) to right LO influences the effects of familiarity on figure-ground perception. Following 20 min of offline anodal stimulation (or sham), participants viewed masked stimuli consisting of two regions separated by a vertical border and were asked to report which region they perceived as figure. One region was the “critical” region, which either depicted a portion of a familiar object (“Familiar” stimuli), or a familiar object with its parts rearranged into a novel configuration (“Part-rearranged” stimuli). Previous research using these stimuli has found higher reports of the critical region as figure for Familiar vs. Part-rearranged displays, demonstrating the effect of familiarity on figure assignment. The results of the current study showed that HD-tDCS to right LO significantly influenced this typical behavioral pattern. Specifically, stimulation (vs. sham) increased reports of the critical region as figure for Part-rearranged stimuli, bringing perception of these displays up to the level of the Familiar stimuli. We interpret this finding as evidence that stimulation of right LO increased participants' reliance on the familiarity of the parts in their figure-ground judgements—a finding consistent with and extending previous research showing that LO is indeed sensitive to object parts. This is the first study showing that HD-tDCS to LO can influence the effects of familiarity on figure-ground perception.

先前的工作表明，枕骨外侧皮质（LO）涉及物体及其部位的识别，以及该物体（或“图”）与其背景的隔离。但是，没有研究检查过非侵入性脑刺激如何影响LO的功能，尤其是在有图形背景的感知任务中。本研究测试了向右LO的高清经颅直流电刺激（HD-tDCS）是否会影响熟悉度对图形地面感知的影响。在离线阳极刺激（或假刺激）20分钟后，参与者查看了由两个区域（由垂直边框分隔）组成的掩盖刺激，并要求他们报告他们认为哪个区域是图形。一个区域是“关键”区域，它描绘了一部分熟悉的物体（“熟悉的”刺激），或熟悉的物体，其零件重新排列成新颖的配置（“零件重新排列”的刺激）。以前使用这些刺激进行的研究发现，对于关键区域的图形，如熟悉的显示器与部分重新排列的显示器，有更高的报告，证明了熟悉度对图形分配的影响。当前研究的结果表明，向右LO的HD-tDCS显着影响了这种典型的行为模式。具体而言，刺激（相对于假手术）增加了关键区域的报告，如部分重排的刺激图所示，使这些显示的感觉达到了熟悉刺激的水平。我们将这一发现解释为对右LO的刺激会增加参与者的抵抗力的证据。依靠部分人物在地物判断中的熟悉程度，这一发现与先前的研究相一致并扩展了研究结果，表明LO确实对对象部分很敏感。这是第一项研究，表明HD-tDCS对LO可以影响熟悉度对图形背景感知的影响。