Department of Psychology, Emory University, Atlanta, Georgia 30322.
Department of Psychology, Emory University, Atlanta, Georgia 30322
J Neurosci. 2018 Nov 28;38(48):10295-10304. doi: 10.1523/JNEUROSCI.1200-18.2018. Epub 2018 Oct 22.
When entering an environment, we can use the present visual information from the scene to either recognize the kind of place it is (e.g., a kitchen or a bedroom) or navigate through it. Here we directly test the hypothesis that these two processes, what we call "scene categorization" and "visually-guided navigation", are supported by dissociable neural systems. Specifically, we manipulated task demands by asking human participants (male and female) to perform a scene categorization, visually-guided navigation, and baseline task on images of scenes, and measured both the average univariate responses and multivariate spatial pattern of responses within two scene-selective cortical regions, the parahippocampal place area (PPA) and occipital place area (OPA), hypothesized to be separably involved in scene categorization and visually-guided navigation, respectively. As predicted, in the univariate analysis, PPA responded significantly more during the categorization task than during both the navigation and baseline tasks, whereas OPA showed the complete opposite pattern. Similarly, in the multivariate analysis, a linear support vector machine achieved above-chance classification for the categorization task, but not the navigation task in PPA. By contrast, above-chance classification was achieved for both the navigation and categorization tasks in OPA. However, above-chance classification for both tasks was also found in early visual cortex and hence not specific to OPA, suggesting that the spatial patterns of responses in OPA are merely inherited from early vision, and thus may be epiphenomenal to behavior. Together, these results are evidence for dissociable neural systems involved in recognizing places and navigating through them. It has been nearly three decades since Goodale and Milner demonstrated that recognizing objects and manipulating them involve distinct neural processes. Today we show the same is true of our interactions with our environment: recognizing places and navigating through them are neurally dissociable. More specifically, we found that a scene-selective region, the parahippocampal place area, is active when participants are asked to categorize a scene, but not when asked to imagine navigating through it, whereas another scene-selective region, the occipital place area, shows the exact opposite pattern. This double dissociation is evidence for dissociable neural systems within scene processing, similar to the bifurcation of object processing described by Goodale and Milner (1992).
当进入一个环境时，我们可以利用场景中的当前视觉信息来识别它是什么类型的地方（例如，厨房或卧室）或在其中导航。在这里，我们直接检验了以下假设，即这两个过程，我们称之为“场景分类”和“视觉引导导航”，由可分离的神经系统支持。具体来说，我们通过要求人类参与者（男性和女性）在场景图像上执行场景分类、视觉引导导航和基线任务来操纵任务需求，并测量两个场景选择性皮质区域（内侧颞叶旁回区和枕叶区）内的平均单变量反应和多变量空间模式，假设它们分别参与场景分类和视觉引导导航。正如预测的那样，在单变量分析中，PPA 在分类任务中的反应明显高于导航和基线任务，而 OPA 则完全相反。同样，在多变量分析中，线性支持向量机在 PPA 中实现了对分类任务的高于机会的分类，但在导航任务中没有。相比之下，在 OPA 中，导航和分类任务都实现了高于机会的分类。然而，在早期视觉皮层中也发现了这两个任务的高于机会的分类，因此不仅仅是 OPA 特有的，这表明 OPA 中反应的空间模式仅仅是从早期视觉继承而来的，因此可能与行为无关。总之，这些结果为涉及识别和导航的可分离神经系统提供了证据。自从 Goodale 和 Milner 证明识别物体和操纵物体涉及不同的神经过程以来，已经将近三十年了。今天，我们表明我们与环境的互动也是如此：识别地点和在其中导航是神经可分离的。更具体地说，我们发现，当要求参与者对场景进行分类时，一个场景选择性区域，即内侧颞叶旁回区，是活跃的，但当要求他们想象在其中导航时，它不是活跃的，而另一个场景选择性区域，即枕叶区，表现出完全相反的模式。这种双重分离是场景处理中可分离神经系统的证据，类似于 Goodale 和 Milner（1992 年）描述的物体处理的分叉。
