Brain networks that produce word finding difficulty for person's name in old people

人们经常说，虽然年龄的增长增加了词汇量，但随着年龄的增长，检索单词，特别是人名等专有名称变得困难。事实上，我们过去对单词提取(词汇流利性任务)的研究表明，老年人在代表动物(例如哺乳动物、鱼类等)的单词方面的提取成绩大约是年轻学生的75%。在这个项目中，我们做了一项PET激活研究，在词汇流畅任务中，大脑区域被激活，对语义类别，如动画、无生命和名人的专有名称，以及语音类别(提取以预先指定的音节开头的单词)，大脑区域被激活。我们发现，在年轻的正常受试者中，对动画、无生命和语音线索的语言流利性激活了包括左侧颞回后部区域(BA 20，37)在内的颞叶…左侧额叶下回(BA44，45)。左侧颞回被解释为处理词汇语义，而左侧额叶回被解释为根据语义和语音信息选择合适的单词。在专名提取中，更多的头区被激活，即左侧颞叶皮质的前部区域(BA22，38)，以及包括额叶极点和内侧额叶皮质(BA10)的区域，前者涉及深层语义加工，后者更多地参与词选择的控制加工。我们还观察到老年人在语义类别(无生命和专有名称)和语音线索的言语流畅过程中的激活区域，发现几乎相同的区域被激活，但其体积趋于较小。最近，一些研究人员报道，在朗读单词等语言任务中，老年人和年轻人的激活区域不同。反映出两组在单词或句子加工上的差异。然而，大脑的萎缩随着年龄的增长而增加，而且萎缩对语言和认知的影响尚未阐明。我们使用一种名为VBM(基于体素的形态测量)的软件来检测与年龄相关的脑萎缩，该软件基于77名年轻人和23名老年人的MRI脑图像。结果发现，正常老年人不同脑区均表现为局限性萎缩，而表现为锡氏裂周围、额下区至顶下区、双侧额叶前内侧区和小脑上区。研究发现，左侧后后回是唯一与年龄相关的萎缩没有重叠的区域，这表明老年人语言流利性不足至少部分可归因于脑萎缩。较少

It is often said that while aging increases vocabulary, retrieval of words, especially proper names such as person's names, becomes difficult with increasing age. Indeed, our past research on word retrieval (verbal fluency task) revealed that the retrieval performance of elderly people was approximately 75 % of younger students for words representing animate (e.g., mammals, fishes, etc.) or inanimate (vehicles, tools, etc.), and only 55 % for proper names (names of politicians, actresses, etc).In this project we did a PET activation study in which brain regions activated during verbal fluency tasks for semantic categories like animates, inanimate and proper names of famous persons, as well as phonological categories (retrieving words beginning with a pre-specified syllable) were explored. We found that in young normal subjects verbal fluency for animates, inanimate and phonological cues activated areas including inferoposterior region of the left temporal gyrus (BA 20,37) to a temporop … More arietal junction, and the left inferior frontal gyrus (BA44,45). Whereas the left temporal gyrus was interpreted to process word semantics, the left frontal gyrus was interpreted to play a role in selecting an appropriate word based on semantic and phonological information. In proper name retrieval, more rostal areas were activated, i.e., the anterior region of the left temporal cortex (BA22,38), and a region including the frontal pole and medial frontal cortex (BA10), the former associating deep semantic processing and the latter more controlled processing of word selection.We also observed activated areas during verbal fluency for semantic categories (inanimate and proper names) and phonological cues in aged people, and found almost the same areas are activated, but their volumes tend to be smaller.Recently, some researchers report that activated areas during language tasks like reading aloud words are different in elderly and young subjects, reflecting differential word or sentence processing in the two groups. However, atrophy of the brain grows with increasing age, and influence of atrophy on language and cognition has not been elucidated. We examined age-related brain shrinkage using a software called VBM(Voxel Based Morphometry) based on MRI brain images of 77 young and 23 old people. It was found that the normal elderly did not show a uniform atrophy regardless of the brain region, rather they showed restricted atrophy in a region surrounding the Syrvian fissure, inferior frontal to inferior parietal region, anteromedial frontal area of both hemispheres, and superior cerebellum. It was found that the left inferoposterior temporal gyrus is an only region that does not overlap with the age-related shrinkage, suggesting that deficient verbal fluency in the elderly is attributable at least in part to brain atrophy. Less