Ritchie J Brendan, Andrews Spencer, Vaziri-Pashkam Maryam, Baker Christopher I
The Laboratory of Brain and Cognition, The National Institute of Mental Health, MD, USA.
Department of Psychological and Brain Sciences, University of Delaware, Newark, DE, USA.
bioRxiv. 2024 Feb 22:2024.02.20.581258. doi: 10.1101/2024.02.20.581258.
Extrastriatal visual cortex is known to exhibit distinct response profiles to complex stimuli of varying ecological importance (e.g., faces, scenes, and tools). The dominant interpretation of these effects is that they reflect activation of distinct "category-selective" brain regions specialized to represent these and other stimulus categories. We sought to explore an alternative perspective: that the response to these stimuli is determined less by whether they form distinct categories, and more by their relevance to different forms of natural behavior. In this regard, food is an interesting test case, since it is primarily distinguished from other objects by its edibility, not its appearance, and there is evidence of food-selectivity in human visual cortex. Food is also associated with a common behavior, eating, and food consumption typically also involves the manipulation of food, often with the hands. In this context, food items share many properties in common with tools: they are graspable objects that we manipulate in self-directed and stereotyped forms of action. Thus, food items may be preferentially represented in extrastriatal visual cortex in part because of these shared affordance properties, rather than because they reflect a wholly distinct kind of category. We conducted fMRI and behavioral experiments to test this hypothesis. We found that behaviorally graspable food items and tools were judged to be similar in their action-related properties, and that the location, magnitude, and patterns of neural responses for images of graspable food items were similar in profile to the responses for tool stimuli. Our findings suggest that food-selectivity may reflect the behavioral affordances of food items rather than a distinct form of category-selectivity.
已知纹外视觉皮层对具有不同生态重要性的复杂刺激（如面孔、场景和工具）表现出不同的反应特征。对这些效应的主流解释是，它们反映了专门用于表征这些及其他刺激类别的不同“类别选择性”脑区的激活。我们试图探索另一种观点：对这些刺激的反应较少取决于它们是否形成不同类别，而更多取决于它们与不同形式自然行为的相关性。在这方面，食物是一个有趣的测试案例，因为它主要通过可食用性而非外观与其他物体区分开来，并且有证据表明人类视觉皮层中存在食物选择性。食物还与一种常见行为——进食相关，而且食物消费通常还涉及对食物的操作，通常是用手。在这种背景下，食物与工具具有许多共同属性：它们是我们以自我导向和刻板的行动形式进行操作的可抓握物体。因此，食物可能在纹外视觉皮层中被优先表征，部分原因是这些共同的可供性属性，而不是因为它们反映了一种完全不同的类别。我们进行了功能磁共振成像（fMRI）和行为实验来检验这一假设。我们发现，行为上可抓握的食物和工具在与行动相关的属性方面被判断为相似，并且可抓握食物图像的神经反应位置、幅度和模式在轮廓上与工具刺激的反应相似。我们的研究结果表明，食物选择性可能反映了食物的行为可供性，而不是一种独特的类别选择性形式。
