Kurth Sophie, Moyse Evelyne, Bahri Mohamed A, Salmon Eric, Bastin Christine
Cyclotron Research Center, University of Liège, Belgium.
Department of Psychology: Cognition and Behavior, University of Liège, Belgium.
Cortex. 2015 Jun;67:59-73. doi: 10.1016/j.cortex.2015.03.013. Epub 2015 Apr 1.
Studies have reported that patients in the severe stages of Alzheimer's disease (AD) experience difficulties recognizing their own faces in recent photographs. Two case reports of late-stage AD showed that this loss of self-face recognition was temporally graded: photographs from the remote past were recognized more easily than more recent photographs. Little is known about the neural correlates of own face recognition abilities in AD patients, while neuroimaging studies in healthy adults have related these abilities to a bilateral fronto-parieto-occipital network. In this study, two behavioral experiments (experiments 1 and 2) and one functional magnetic resonance imaging (fMRI) experiment (second part of experiment 2) were conducted to compare mild AD patients (experiment 1) and moderate AD patients (experiment 2) with healthy older participants in a recognition task involving self and familiar faces from different decades of the participants' life. In moderate AD patients, variable performance allowed us to examine correlations between scores and resting-state fMRI in order to link behavioral data to cerebral activity. At the behavioral level, the results revealed that, in mild AD, self and familiar face recognition was preserved. Moreover, mild AD patients and healthy older participants showed an inverse temporal gradient, with faster recognition of self and familiar recent photographs than self and familiar remote photographs. However, in moderate AD, both self and familiar face recognition were affected. fMRI results showed that the higher the connectivity between the dorsomedial prefrontal cortex (dMPFC) and the right superior frontal gyrus (rSFG), the lower the self and familiar face recognition scores in moderate AD patients. Given that previous studies have related the superior frontal region to control processes rather than face recognition processes, these results might reflect less segregation and more interference between brain networks in AD. In other words, impaired face recognition in AD may be related to functional dedifferentiation of specific brain regions.
研究报告称，阿尔茨海默病（AD）重度阶段的患者在识别近期照片中的自己的面孔时存在困难。两份晚期AD的病例报告显示，这种自我面孔识别能力的丧失存在时间梯度：相较于近期照片，更容易识别来自遥远过去的照片。关于AD患者自我面孔识别能力的神经关联知之甚少，而针对健康成年人的神经影像学研究已将这些能力与双侧额顶枕网络联系起来。在本研究中，进行了两项行为实验（实验1和实验2）以及一项功能磁共振成像（fMRI）实验（实验2的第二部分），以在一项涉及参与者生活中不同年代的自我和熟悉面孔的识别任务中，将轻度AD患者（实验1）和中度AD患者（实验2）与健康老年参与者进行比较。在中度AD患者中，表现的变异性使我们能够检查分数与静息态fMRI之间的相关性，以便将行为数据与大脑活动联系起来。在行为层面，结果显示，在轻度AD中，自我和熟悉面孔识别能力得以保留。此外，轻度AD患者和健康老年参与者呈现出相反的时间梯度，识别自我和熟悉的近期照片比识别自我和熟悉的遥远照片更快。然而，在中度AD中，自我和熟悉面孔识别均受到影响。fMRI结果显示，在中度AD患者中，背内侧前额叶皮质（dMPFC）与右侧额上回（rSFG）之间的连接性越高，自我和熟悉面孔识别分数越低。鉴于先前的研究已将额上区域与控制过程而非面孔识别过程联系起来，这些结果可能反映出AD患者大脑网络之间的分离减少且干扰增多。换句话说，AD中面孔识别受损可能与特定脑区的功能去分化有关。
