Otsuka Sachio, Saiki Jun
Faculty of Culture and Information Science, Doshisha University, Japan.
Graduate School of Human and Environmental Studies, Kyoto University, Japan.
Heliyon. 2019 Dec 24;5(12):e03032. doi: 10.1016/j.heliyon.2019.e03032. eCollection 2019 Dec.
Behavioral and neuroscience studies have shown that we can easily identify material categories, such as metal and fabric. Not only the early visual areas but also higher-order visual areas including the fusiform gyrus are known to be engaged in material perception. However, the brain mechanisms underlying visual short-term memory (VSTM) for material categories are unknown. To address this issue, we examined the neural correlates of VSTM for objects with material categories using a change detection task. In each trial, participants viewed a sample display containing two, four, or six objects having six material categories and were required to remember the locations and types of objects. After a brief delay, participants were asked to detect an object change based on the images or material categories in the test display (image-based and material-based conditions). Neuronal activity in the brain was assessed using functional magnetic resonance imaging (MRI). Behavioral results showed that the number of objects encoded did not increase as a function of set size in either image-based or material-based conditions. By contrast, MRI data showed a difference between the image-based and material-based conditions in percent signal change observed in a priori region of interest, the fusiform face area (FFA). Thus, we failed to achieve our research aim. However, the brain activation in the FFA correlated with the activation in the precentral/postcentral gyrus, which is related to haptic processing. Our findings indicate that the FFA may be involved in VSTM for objects with material categories in terms of the difference between images and material categories and that this memory may be mediated by the tactile properties of objects.
行为学和神经科学研究表明，我们能够轻松识别材料类别，比如金属和织物。不仅早期视觉区域，包括梭状回在内的高阶视觉区域也被认为参与了材料感知。然而，关于材料类别的视觉短期记忆（VSTM）背后的脑机制尚不清楚。为了解决这个问题，我们使用变化检测任务研究了具有材料类别的物体的VSTM的神经关联。在每次试验中，参与者观看一个包含两个、四个或六个具有六种材料类别的物体的样本显示，并被要求记住物体的位置和类型。短暂延迟后，要求参与者根据测试显示中的图像或材料类别检测物体变化（基于图像和基于材料的条件）。使用功能磁共振成像（MRI）评估大脑中的神经元活动。行为结果表明，在基于图像或基于材料的条件下，编码的物体数量并未随集合大小而增加。相比之下，MRI数据显示，在先验感兴趣区域梭状面孔区（FFA）观察到的基于图像和基于材料的条件在信号变化百分比上存在差异。因此，我们未能实现研究目标。然而，FFA中的大脑激活与中央前回/中央后回中的激活相关，这与触觉处理有关。我们的研究结果表明，就图像和材料类别之间的差异而言，FFA可能参与了具有材料类别的物体的VSTM，并且这种记忆可能由物体的触觉属性介导。
