PRIMING DEFICITS & BRAIN SYSTEMS IN DEMENTIA & AMNESIA

启动是内隐记忆的一种形式，指的是 仅仅处理一个项目就可以促进该项目的后续处理， 一样的东西。 启动效应可以在没有意识的情况下发生 回忆起以前的研究情节，因此， 提示启动和外显记忆是由不同的 记忆系统 来自记忆障碍患者的证据对于 这一假设，因为如果有可能联系的崩溃， 外显记忆和引发对不同大脑区域的损害， 会强化独立记忆系统假说 许多研究 在健忘症患者中发现了正常的启动效应， 研究人员报告说，老年痴呆症患者的启动功能受损， 疾病 然而，许多困难与评估有关， 记忆受损受试者的启动效应。 所述起动措施可以 比外显记忆测量更不敏感，并且缺乏组 差异可以简单地反映低测量灵敏度。 程度 在给定的任务中获得的启动与加工效率有关 (i.e.基线性能），处理效率较低， 更大的启动。 因此，如果患者有轻微的处理， 这可能掩盖了启动障碍。 拟建项目 由一系列实验组成， 性能水平和启动措施的敏感性。 正常 将调查对照受试者和三组患者; 可能患有阿尔茨海默病的患者，患有亨廷顿病的患者 疾病和健忘症患者。 这些患者群体在以下方面不同： 他们的外显记忆缺陷的严重程度，以及在何种程度上， 词汇/感知处理效率受到损害。 年轻正常人 受试者也将被纳入研究。 因此， 可以确定是否记忆功能下降导致的 健忘症或痴呆症在性质上类似于功能衰退 与正常的衰老过程有关。 除了行为 测量，测量特定大脑结构的体积损失， 从MRI中获得。 这些大脑测量将与 行为指数，使用多元回归方法，以确定 每个大脑区域在感知/词汇处理中的具体作用， 外显记忆和启动强度。 具体假设 行为和结构脑测量之间的关系 我们以前的工作将被测试。

Priming is a form of implicit memory, and refers to the fact that the mere processing of an item can facilitate subsequent processing of that same item. Priming effects can occur in the absence of conscious recollection of the prior study episode, and it has, therefore, been suggested that priming and explicit memory are mediated by different memory systems. Evidence from memory disordered patients is critical for this hypothesis, since if it is possible to link the breakdown of explicit memory and priming to damage to different brain regions this would strengthen the independent memory systems hypothesis. Many studies have found normal priming effects in amnesic patients and some investigators have reported impaired priming in patients with Alzheimer's disease. However, many difficulties are associated with evaluating priming effects in memory impaired subjects. The priming measures may be less sensitive than explicit memory measures, and the lack of group differences may simply reflect low measurement sensitivity. The degree of priming obtained in a given task is related to processing efficiency (i.e. baseline performance), with less efficient processing resulting in greater priming. Therefore, if patients have even mild processing deficits this may mask priming impairments. The proposed project consists of a series of experiments designed to manipulate baseline performance level and sensitivity of the priming measures. Normal control subjects and three groups of patients will be investigated; patients with probable Alzheimer's disease, patients with Huntington's disease, and amnesic patients. These patient groups differ in the severity of their explicit memory defects, and in the extent to which lexical/perceptual processing efficiency is compromised. Younger normal subjects will also be included in the study. Therefore, it will be possible to determine if the decline in memory function resulting from amnesia or dementia is qualitatively similar to the decline in function associated with the normal aging process. In addition to the behavioral measures, measures of volume loss in specific brain structures will be obtained from MRI. These brain measures will be related to the behavioral indices, using a multiple regression approach, to determine the specific role of each brain region in perceptual/lexical processing, explicit memory, and strength of priming. Specific hypotheses about the relationship between the behavioral and structural brain measures derived from our previous work will be tested.