INHIBITION OF EXOGENOUS ORIENTING AND AGING

研究建议的广泛长期目标包括 开发一项行为和神经科学研究计划，检查 以一种新的方式抑制衰老，抑制外源性定向。 具体地说，将检查健康的老年人是否可以抑制 内源性注意集中时的外源性定向 年轻人就是这样做的。注意的定向和抑制 认知机制是正常和异常的中心方面 年轻人和老年人的行为。在两个实验中，健康的杨格 老年人会执行外源性定向任务， 内源性注意要么集中，要么分散(在被试内部)。 内源性注意状态是由指令决定的。外源 注意由突然出现的外围提示(正方形)在 下一个目标字母的位置(有效提示，50% 概率)或非目标编号(无效提示，50%概率)。 外围提示-目标间隔将有所不同(200、500、700毫秒)。目标字母 类别(元音或辅音)需要按下右手或左手按钮 (平衡)。事件相关脑电位将收集在 实验2.在这两个实验中，内源性注意焦点将是 通过渔获量试验进行评估，在每个试验区块内随机提供 以及在没有提供外围提示的情况下，以及 目标信函出现在指定的五个位置之一 分散注意状态的范围。不抑制外源物质 定向将发生在内源性注意力分散时(乔尼德斯， (1981年)。然而，如果老年人有与以下方面有关的抑制缺陷 额叶注意功能(Kramer.1994年)，那么他们应该 内源性时抑制外源性定向的困难(较慢) 与年轻人不同，注意力是集中的(Yantis&Jonides，1990)。 外源性定向抑制和年龄差异将调节 N1事件相关电位分量的幅度。

Broad long term objectives of the research proposal include the development of a behavioral and neuroscience research program examining aging and inhibition in a new way, the inhibition of exogenous orienting. Specifically, it will be examined whether healthy older adults can inhibit exogenous orienting when endogenous attention is focused as well as younger adults do. Both the orienting of attention and the inhibitory mechanisms in cognition are central aspects to both normal and abnormal behavior in younger and older adults. In two experiments healthy younger and older adults will perform an exogenous orienting task in which endogenous attention is either focused or dispersed (within-subjects). Endogenous attention state is determined by instruction. Exogenous attention is oriented by an abrupt onset peripheral cue (square) at the location of either the subsequent target letter (valid cue, 50% probability) or nontarget number (invalid cue, 50% probability). Peripheral cue-target interval will vary (200, 500, 700 ms). Target letter category (vowel or consonant) requires a right or left hand button press (counterbalanced). Event-related brain potentials will be collected in Experiment 2. For both experiments, endogenous attention focus will be assessed with catch trials, randomly presented within each block of trials and across conditions, in which no peripheral cue is presented, and a target letter is presented at one of five locations within the designated range of the dispersed attention state. No inhibition of exogenous orienting will occur when endogenous attention is dispersed (Jonides, 1981). However, if older adults have inhibition deficits related to frontal lobe attentional functioning (Kramer. 1994), then they should have difficulty (be slower) inhibiting exogenous orienting when endogenous attention is focused, unlike younger adults (Yantis & Jonides, 1990). Exogenous orienting inhibition, and age differences, will modulate the amplitude of the N1 ERP component.