Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, United States of America.
PLoS Biol. 2011 Apr;9(4):e1000608. doi: 10.1371/journal.pbio.1000608. Epub 2011 Apr 5.
Defining the exact mechanisms by which the brain processes visual objects and scenes remains an unresolved challenge. Valuable clues to this process have emerged from the demonstration that clusters of neurons ("modules") in inferior temporal cortex apparently respond selectively to specific categories of visual stimuli, such as places/scenes. However, the higher-order "category-selective" response could also reflect specific lower-level spatial factors. Here we tested this idea in multiple functional MRI experiments, in humans and macaque monkeys, by systematically manipulating the spatial content of geometrical shapes and natural images. These tests revealed that visual spatial discontinuities (as reflected by an increased response to high spatial frequencies) selectively activate a well-known place-selective region of visual cortex (the "parahippocampal place area") in humans. In macaques, we demonstrate a homologous cortical area, and show that it also responds selectively to higher spatial frequencies. The parahippocampal place area may use such information for detecting object borders and scene details during spatial perception and navigation.
确定大脑处理视觉对象和场景的确切机制仍然是一个未解决的挑战。有价值的线索表明，下颞叶皮层中的神经元簇（“模块”）显然对特定类别的视觉刺激（如地点/场景）有选择性的反应。然而，更高阶的“类别选择性”反应也可能反映特定的较低层次的空间因素。在这里，我们通过在人类和猕猴中进行多项功能磁共振成像实验，系统地操纵几何形状和自然图像的空间内容，检验了这一观点。这些测试表明，视觉空间不连续性（如对高空间频率的反应增加所反映的那样）选择性地激活了人类视觉皮层中一个著名的位置选择性区域（“海马旁回位置区”）。在猕猴中，我们证明了一个同源的皮质区域，并表明它也对较高的空间频率有选择性的反应。海马旁回位置区可能会在空间感知和导航过程中利用这些信息来检测物体边界和场景细节。
