PRIMING DEFICITS & BRAIN SYSTEMS IN DEMENTIA & AMNESIA

描述（改编自研究者摘要）：预充是一种 内隐记忆，指的是仅仅处理一个项目的事实， 可以促进相同项目的后续处理。 启动效应可以 发生在没有对先前研究事件的有意识回忆的情况下， 并且已经表明，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表明， 这对这一假设至关重要，因为如果有可能将故障 外显记忆和启动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， 已经报道了阿尔茨海默病患者的启动受损。 然而，许多困难与评估启动效应有关， 记忆力受损的实验对象 启动措施可能不如 外显记忆测量，以及启动缺乏组间差异 测量可能仅仅反映低测量灵敏度。 程度 在给定任务中获得的启动与处理效率有关（即， 基线性能），处理效率较低， 启动 因此，如果患者有轻微的处理缺陷， 面罩启动损伤。 拟议项目包括一系列 实验旨在操纵基线性能和灵敏度， 启动措施。 成人年龄范围内的正常对照受试者 将对三组患者进行研究;可能患有 阿尔茨海默病、亨廷顿病和健忘症患者 患者 这些患者群体在其明确的严重程度不同， 记忆缺陷和不同成分处理的程度 对他们的基线性能有贡献的人会受到损害。 除了 行为测量，测量特定大脑中的体积损失， 将从MRI获得结构。 这些大脑测量将与 行为指数，使用多元回归方法， 确定每个大脑区域在基线处理中的具体作用 速度、外显记忆和启动强度。 具体假设 大脑行为和结构测量之间的关系 将测试来自研究者先前研究的结果。

DESCRIPTION (adapted from investigator's abstract): 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 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 on priming measures 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 and sensitivity of the priming measures. Normal control subjects across the adult age range and three groups of patients will be investigated; patients with probable Alzheimer's disease, patients with Huntington's disease and amnestic patients. These patient groups differ in the severity of their explicit memory deficits and in the extent to which different component processes contributing to their baseline performance are compromised. 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 baseline processing speed, explicit memory, and strength of priming. Specific hypotheses about the relationship between the behavioral and structural brain measures derived from the investigators' previous studies will be tested.