Clarke Alex, Pell Philip J, Ranganath Charan, Tyler Lorraine K
University of Cambridge, UK.
University of California, Davis.
J Cogn Neurosci. 2016 Jul;28(7):1010-23. doi: 10.1162/jocn_a_00951. Epub 2016 Mar 11.
The human ventral temporal cortex (VTC) plays a critical role in object recognition. Although it is well established that visual experience shapes VTC object representations, the impact of semantic and contextual learning is unclear. In this study, we tracked changes in representations of novel visual objects that emerged after learning meaningful information about each object. Over multiple training sessions, participants learned to associate semantic features (e.g., "made of wood," "floats") and spatial contextual associations (e.g., "found in gardens") with novel objects. fMRI was used to examine VTC activity for objects before and after learning. Multivariate pattern similarity analyses revealed that, after learning, VTC activity patterns carried information about the learned contextual associations of the objects, such that objects with contextual associations exhibited higher pattern similarity after learning. Furthermore, these learning-induced increases in pattern information about contextual associations were correlated with reductions in pattern information about the object's visual features. In a second experiment, we validated that these contextual effects translated to real-life objects. Our findings demonstrate that visual object representations in VTC are shaped by the knowledge we have about objects and show that object representations can flexibly adapt as a consequence of learning with the changes related to the specific kind of newly acquired information.
人类腹侧颞叶皮层(VTC)在物体识别中起着关键作用。虽然视觉经验塑造VTC物体表征这一点已得到充分证实,但语义和情境学习的影响尚不清楚。在本研究中,我们追踪了在学习关于每个物体的有意义信息后出现的新型视觉物体表征的变化。在多个训练环节中,参与者学会将语义特征(如“由木头制成”“漂浮”)和空间情境关联(如“在花园中发现”)与新型物体联系起来。功能性磁共振成像(fMRI)被用于检测学习前后物体的VTC活动。多变量模式相似性分析显示,学习后,VTC活动模式携带了关于物体所学情境关联的信息,使得具有情境关联的物体在学习后表现出更高的模式相似性。此外,这些由学习引起的关于情境关联的模式信息增加与物体视觉特征的模式信息减少相关。在第二个实验中,我们验证了这些情境效应可转化到现实生活中的物体上。我们的研究结果表明,VTC中的视觉物体表征是由我们对物体的知识塑造的,并表明物体表征可以因学习而灵活适应,与新获取的特定类型信息的变化相关。