INHIBITION OF EXOGENOUS ORIENTING AND AGING

研究建议的长远目标包括 发展行为和神经科学研究项目， 衰老和抑制的新途径，外源性定向抑制。 具体而言，将检查健康的老年人是否可以抑制 当内源性注意力集中时， 年轻的成年人做。注意力的定向和抑制性 认知机制是正常和异常的核心方面 年轻人和老年人的行为。在两个实验中， 老年人会执行一个外源性的定向任务， 内源性注意力是集中的或分散的（受试者内）。 内源性注意状态是由指令决定的。外源 注意力是由一个突然出现的周边线索（正方形）在 后续目标字母的位置（有效提示，50% 概率）或非目标数字（无效提示，50%概率）。 外围提示-目标间隔将有所不同（200、500、700 ms）。目标字母 类别（元音或辅音）需要按下右手或左手按钮 （平衡）。事件相关脑电位将在 实验2.对于这两个实验，内源性注意力集中将是 通过捕捞试验进行评估，在每个试验区组中随机呈现 和跨条件，其中没有外围线索，和 目标字母出现在指定的五个位置之一 分散注意力状态的范围。无外源性抑制 定向将在内源性注意力分散时发生（Jonides， 1981年）。然而，如果老年人有与 额叶注意功能（克雷默. 1994年，他们应该 当内源性时，抑制外源性定向的困难（较慢） 注意力集中，不像年轻的成年人（Yantis & Jonides，1990）。 外源性定向抑制和年龄差异将调节 N1 ERP成分的振幅。

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.