FRONTAL CONTROL /MEMORY IN AGING & SENILE DEMENTIA OF THE ALZHEIMER'S TYPE

老年痴呆症的阿尔茨海默型（SDAT）正在成为一个最 严重的健康问题 初始阶段 疾病，个体经历一些记忆障碍，随后 大多数认知功能的广泛崩溃。 另外虽然 赤字不那么严重和渐进，也有证据表明， 健康老年人的认知障碍。 的目标 目前的建议是研究一种认知机制，它可能是 在健康老年人和SDAT个体中表现出的缺陷， 开始开发一个正式的模型来解释这些缺陷。 本提案中所述的具体目标机制是 以抑制部分激活和竞争性信息。 最近的工作 从我们的实验室（P01 AG 03991，项目3）表明，健康的老年人 个体和在更大程度上SDAT个体表现出崩溃 在抑制性老年个体中，以及在更大程度上SDAT个体中， 在许多实验中表现出抑制控制的崩溃 范例 在第一系列提出的实验（实验1-7， 系列I），抑制过程在健康老龄化中的效率， SDAT将在多个不同级别进行检查， 信息处理系统：知觉，记忆提取，词汇 消除歧义和句子理解。 另外这些 实验将涉及允许人们追踪的操作 在我们的实验对象中， 组 第二系列实验（实验1-4，系列II） 将为健康的老年人和SDAT个体提供一套正式的 Cohen和Servan-Schreiber开发的连接主义模型 （1992）解释抑制效率的分解 在精神分裂症患者的过程中，也模拟多巴胺能 前额叶皮层的崩溃 拟议的实验将 为正式建模认知变化提供经验基础， 发生在健康的老年人和SDAT个体，也提供了一个独特的 有机会比较特定模型参数的变化， 有必要解释三个阶段认知表现的变化， 不同的人群（精神分裂症，健康老年人和SDAT个体）。 因此，在与J. Cohen和D. Servan-Schreiber我们打算 使用三管齐下的攻击利用基本的认知理论， 联结主义模型和神经学证据， 与健康老龄化相关的认知变化， 老年痴呆症

Senile dementia of the Alzheimer type (SDAT) is becoming one of the most devasting health problems facing society. In the initial stages of the disease, individuals experience some memory impairment followed later by widespread breakdown in most cognitive functions. In addition, although the deficits are not as severe and progressive, there is also evidence of cognitive breakdowns in healthy aged individuals. The goal of the present proposal is to examine a cognitive mechanism which may underlie the deficits exhibited in both healthy aged and in SDAT individuals, and to begin to develop a formal model which can account for these deficits. The specific target mechanism addressed in this proposal is the ability to inhibit partially activated and competitive information. Recent work from our lab (P01AG03991, Project 3) indicates that healthy aged individuals and to a greater extent SDAT individuals exhibit a breakdown in inhibitory aged individuals and to a greater extent SDAT individuals exhibit a breakdown in inhibitory control across a number of experimental paradigms. In the first series of proposed experiments (Experiments 1-7, Series I), the efficiency of inhibitory processes in healthy aging and SDAT will be examined at a number of distinct levels within the information processing system: perception, memory retrieval, lexical disambiguation, and sentence comprehension. In addition, these experiments will involve manipulations that will allow one to track changes in the time course of inhibitory processes across our subjects groups. The second series of experiments (Experiments 1-4, Series II) will extend to healthy aged and SDAT individuals a set of formal connectionist models that were developed by Cohen and Servan-Schreiber (1992) to account for breakdowns in the efficiency of inhibitory processes in schizophrenic individuals and also to simulate dopaminergic breakdowns in the prefrontal cortex. The proposed experiments will provide an empirical base for formally modelling cognitive changes that occur in healthy aged and SDAT individuals, and also provide a unique opportunity to compare changes in the specific model parameters that are necessary to account for changes in cognitive performance across three distinct populations (schizophrenic, healthy aged, and SDAT individuals). Hence, in collaboration with J. Cohen and D. Servan-Schreiber we intend to use a three-pronged attack utilizing basic cognitive theory, formal connectionist modelling, and neurological evidence to better understand the cognitive changes that are associated with healthy aging and Alzheimer's Disease.