Department of Psychology, University of Arizona, Tucson, AZ 85721, USA.
Hippocampus. 2012 Oct;22(10):1965-77. doi: 10.1002/hipo.22065.
Research has demonstrated that the perirhinal cortex (PRC) represents complex object-level feature configurations, and participates in familiarity versus novelty discrimination. Barense et al. [(in press) Cerebral Cortex, 22:11, doi:10.1093/cercor/bhr347] postulated that, in addition, the PRC modulates part familiarity responses in lower-level visual areas. We used fMRI to measure activation in the PRC and V2 in response to silhouettes presented peripherally while participants maintained central fixation and performed an object recognition task. There were three types of silhouettes: Familiar Configurations portrayed real-world objects; Part-Rearranged Novel Configurations created by spatially rearranging the parts of the familiar configurations; and Control Novel Configurations in which both the configuration and the ensemble of parts comprising it were novel. For right visual field (RVF) presentation, BOLD responses revealed a significant linear trend in bilateral BA 35 of the PRC (highest activation for Familiar Configurations, lowest for Part-Rearranged Novel Configurations, with Control Novel Configurations in between). For left visual field (LVF) presentation, a significant linear trend was found in a different area (bilateral BA 38, temporal pole) in the opposite direction (Part-Rearranged Novel Configurations highest, Familiar Configurations lowest). These data confirm that the PRC is sensitive to the agreement in familiarity between the configuration level and the part level. As predicted, V2 activation mimicked that of the PRC: for RVF presentation, activity in V2 was significantly higher in the left hemisphere for Familiar Configurations than for Part-Rearranged Novel Configurations, and for LVF presentation, the opposite effect was found in right hemisphere V2. We attribute these patterns in V2 to feedback from the PRC because receptive fields in V2 encompass parts but not configurations. These results reveal two new aspects of PRC function: (1) it is sensitive to the congruency between the familiarity of object configurations and the parts comprising those configurations and (2) it likely modulates familiarity responses in visual area V2.
研究表明，边缘脑区（PRC）代表复杂的物体水平特征配置，并参与熟悉度与新颖性辨别。Barense 等人[（即将发表）《大脑皮质》，22：11，doi：10.1093/cercor/bhr347]推测，此外，PRC 还调节较低视觉区域中部分熟悉度的反应。我们使用 fMRI 测量 PRC 和 V2 在呈现外周剪影时的激活，同时参与者保持中央注视并执行物体识别任务。有三种类型的剪影：熟悉配置描绘真实世界的物体；部分重新排列的新颖配置通过空间重新排列熟悉配置的部分创建；控制新颖配置，其中配置和组成它的部件集都是新颖的。对于右视野（RVF）呈现，双侧 BA 35 的 BOLD 反应显示 PRC 中存在显著的线性趋势（熟悉配置的激活最高，部分重新排列的新颖配置最低，控制新颖配置在两者之间）。对于左视野（LVF）呈现，在相反方向的另一个区域（双侧 BA 38，颞极）中发现了显著的线性趋势。部分重新排列的新颖配置最高，熟悉配置最低）。这些数据证实 PRC 对配置水平和部件水平之间熟悉度的一致性敏感。正如预测的那样，V2 的激活模仿了 PRC：对于 RVF 呈现，左半球 V2 的活动对于熟悉配置明显高于部分重新排列的新颖配置，而对于 LVF 呈现，在右半球 V2 中发现了相反的效果。我们将 V2 中的这些模式归因于 PRC 的反馈，因为 V2 的感受野包含部件但不包含配置。这些结果揭示了 PRC 功能的两个新方面：（1）它对物体配置的熟悉度与组成这些配置的部件之间的一致性敏感；（2）它可能调节视觉区域 V2 中的熟悉度反应。
