Aging and the cholinergic system on attention and timing

老年人往往受到几种认知过程的损害，包括能力下降。 要集中注意力，要完成多项任务，并要短时间间隔。一些模型显示出密切的相互作用 时间和注意力的关系。拟议中的研究假设注意力和计时涉及相似的大脑。 各区域，特别是额叶的运动区。此外，据预测，额叶功能障碍 运动区是与年龄相关的注意力和计时障碍的原因。这种功能障碍是由于， 部分原因是大细胞基底核胆碱能神经元的丢失。建议数 研究工作如下：1)检查运动皮质损伤和NBM投射对运动的影响 大脑皮质对注意力和时间估计的影响，2)比较大鼠和 人类，3)研究与年龄相关的NBM神经元丢失与注意力损害之间的关系 以及4)研究衰老和脑损伤对注意相关神经元活动的影响。 运动皮质。拟议中的对老鼠和人类的行为研究涉及类似版本的 同步时态处理(STP)任务。在STP任务中，被试学习将听觉和听觉联系起来 具有短和长固定时间间隔的视觉提示，然后测试它们的产生/估计能力 这段时间间隔在不同的注意要求下。在集中注意力的情况下，只有一条线索是 呈现给受试者。在注意力分散的情况下，两个线索都会出现，必须注意 命令才能正确响应。注意力集中状况可作为绩效的基准衡量标准。 中心的经验性问题涉及衰老和损伤(在大鼠中)如何影响分离的 注意条件，相对于集中的注意条件。用标量期望理论进行模型拟合 便于比较人和大鼠的行为数据，并可能提供一个功能 解释衰老和损伤对集中注意力和分散注意力的影响。总体而言，这方面的研究 该提案将增强我们对参与注意力和计时的大脑系统的了解。重要的是 新的信息将被揭示，将阐明与年龄相关的神经机制 注意力和时间上的障碍。这一新知识将为...的发展提供方向 治疗。

The elderly tend to be afflicted with impairments of several cognitive processes, including a decreased ability to pay attention, perform multiple tasks, and to time short intervals. Some models suggest a close interaction of timing and attention. The proposed studies hypothesize that attention and timing involve similar brain regions, in particular motor areas in the frontal lobe. In addition, it is predicted that dysfunction of the frontal motor areas is responsible for the age-related impairments in attention and timing. This dysfunction is due, in part, to the loss of cholinergic neurons of the nucleus basalis magnocellularis (NBM). The proposed studies do the following: 1) examine the effects of damage to motor cortex and NBM projections to motor cortex on attention and time estimation, 2) compare age-related changes of attention and timing in rats and humans, 3) examine the relationship between age-related loss of NBM neurons and impairments in attention and timing, and 4) investigate the effects of aging and brain damage on attention-related neuronal activity in motor cortex. The proposed behavioral studies with rats and humans involve similar versions of a simultaneous temporal processing (STP) task. In the STP task, subjects' learn to associate auditory and visual cues with short and long fixed time intervals, and are then tested on their ability to produce/estimate this time interval under different attentional demands. In a focused attention condition, only one cue is presented to subjects. In a divided attention condition, both cues are presented and must be attended to in order to respond correctly. The focused attention condition serves as a baseline measure of performance. The central empirical question concerns how aging and lesions (in rats) affect timing performance in divided attention conditions, relative to focused attention conditions. Model fits using scalar-expectance theory facilitate comparison between the human and rat behavioral data and potentially provide a functinoal interpretation of the effects of aging and lesions on focused and divided attention. Overall, the studies in this proposal will enhance our knowledge of the brain systems participating in attention and timing. Importantly, new information will be revealed that will elucidate the neural mechanisms responsible for age-related impairments in attention and timing. This new knowledge will provide directions for the development of treatments.