PRIMING DEFICITS & BRAIN SYSTEMS IN DEMENTIA & AMNESIA

启动是内隐记忆的一种形式，指的是 仅仅是对物品的处理就可以促进该物品的后续处理 一样的东西。启动效应可以在没有意识的情况下发生 对先前研究插曲的回忆，因此，它是 提示启动和外显记忆通过不同的中介机制 记忆系统。记忆障碍患者的证据对 这一假设，因为如果有可能将 外显记忆和启动对大脑不同区域的损害 会强化独立记忆系统假说。许多研究 在健忘症患者和一些人身上发现了正常的启动效应 研究人员报告称，阿尔茨海默病患者的启动功能受损 疾病。然而，与评估有关的许多困难 记忆受损受试者的启动效应。启动措施可能 不像外显记忆测量那么敏感，缺乏团队 差异可能只是反映了测量灵敏度较低。学位 在特定任务中获得的启动次数与加工效率有关 (即基准性能)，处理效率较低会导致 更大的引爆力。因此，如果患者有轻微的处理 缺陷这可能掩盖了启动障碍。拟议中的项目 由一系列旨在操纵基线的实验组成 启动措施的绩效水平和敏感性。正常 对照组和三组患者将被调查； 可能患有阿尔茨海默氏症的患者，亨廷顿氏症患者 疾病和健忘症患者。这些患者群体的不同之处在于 他们的外显记忆缺陷的严重程度，以及 词汇/知觉处理效率会受到影响。更年轻的正常 受试者也将被包括在研究中。因此，它将是 有可能确定记忆功能的下降是否由 健忘症或痴呆症本质上类似于功能衰退。 与正常的衰老过程有关。除了行为上的 测量，测量特定大脑结构中的体积损失将是 从核磁共振中得到的。这些大脑测量将与 行为指数，使用多元回归方法，以确定 每个大脑区域在知觉/词汇处理中的具体作用， 外显记忆和启动的强度。关于这一现象的具体假设 行为脑测量与结构脑测量之间的关系 我们之前的工作将得到检验。

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.