Department of Psychology, University of Toronto Toronto, ON, Canada.
Department of Psychology, University of Toronto Toronto, ON, Canada ; Rotman Research Institute Baycrest, Toronto, ON, Canada.
Front Hum Neurosci. 2014 Mar 4;8:117. doi: 10.3389/fnhum.2014.00117. eCollection 2014.
Recent research suggests that the medial temporal lobe (MTL) is involved in perception as well as in declarative memory. Amnesic patients with focal MTL lesions and semantic dementia patients showed perceptual deficits when discriminating faces and objects. Interestingly, these two patient groups showed different profiles of impairment for familiar and unfamiliar stimuli. For MTL amnesics, the use of familiar relative to unfamiliar stimuli improved discrimination performance. By contrast, patients with semantic dementia-a neurodegenerative condition associated with anterolateral temporal lobe damage-showed no such facilitation from familiar stimuli. Given that the two patient groups had highly overlapping patterns of damage to the perirhinal cortex, hippocampus, and temporal pole, the neuroanatomical substrates underlying their performance discrepancy were unclear. Here, we addressed this question with a multivariate reanalysis of the data presented by Barense et al. (2011), using functional connectivity to examine how stimulus familiarity affected the broader networks with which the perirhinal cortex, hippocampus, and temporal poles interact. In this study, healthy participants were scanned while they performed an odd-one-out perceptual task involving familiar and novel faces or objects. Seed-based analyses revealed that functional connectivity of the right perirhinal cortex and right anterior hippocampus was modulated by the degree of stimulus familiarity. For familiar relative to unfamiliar faces and objects, both right perirhinal cortex and right anterior hippocampus showed enhanced functional correlations with anterior/lateral temporal cortex, temporal pole, and medial/lateral parietal cortex. These findings suggest that in order to benefit from stimulus familiarity, it is necessary to engage not only the perirhinal cortex and hippocampus, but also a network of regions known to represent semantic information.
最近的研究表明，内侧颞叶（MTL）不仅参与了陈述性记忆，还参与了知觉。有局灶性 MTL 损伤的遗忘症患者和语义痴呆症患者在辨别面孔和物体时表现出知觉缺陷。有趣的是，这两组患者对熟悉和不熟悉的刺激表现出不同的损伤模式。对于 MTL 遗忘症患者，与不熟悉的刺激相比，使用熟悉的刺激可提高辨别表现。相比之下，语义痴呆症患者（一种与前外侧颞叶损伤相关的神经退行性疾病）没有表现出这种熟悉刺激的促进作用。鉴于这两组患者的眶回、海马体和颞极的损伤模式高度重叠，其表现差异的神经解剖学基础尚不清楚。在这里，我们使用 Barense 等人（2011 年）提出的数据的多元重新分析来解决这个问题，使用功能连接来检查刺激熟悉度如何影响与眶回、海马体和颞极相互作用的更广泛网络。在这项研究中，健康参与者在进行涉及熟悉和新颖面孔或物体的异常感知任务时接受了扫描。基于种子的分析显示，右侧眶回和右侧前海马体的功能连接受刺激熟悉度的调节。与不熟悉的面孔和物体相比，右侧眶回和右侧前海马体与额侧/外侧颞叶、颞极和内侧/外侧顶叶的功能相关性增强。这些发现表明，为了受益于刺激熟悉度，不仅需要眶回和海马体，还需要涉及已知代表语义信息的区域的网络。
