Capacity Limits in Multi-Tasking

描述(申请人提供)：人类表现出严重的能力限制：一个人几乎不能记住3到4个项目，或者一次执行多项任务。这项研究计划的目标是利用神经成像工具发展对限制我们同时处理多项任务的能力的中枢机制的理解。 由于双任务干扰是由于两个感觉-运动通道不能独立处理信息而引起的，本研究将绘制出感觉输入或运动输出都不重叠的感觉运动任务中的信息神经流动。其他研究将专门针对这条信息通路上的反应选择阶段，因为这是最常与双重任务限制相关的认知过程。新的fMRI计时方法将被用来分离参与反应选择的大脑区域，并确定它们在信息通路中的作用。此外，这些研究将评估是否既有任务特定的反应选择底物，也有通用反应选择底物。 神经信息通路的建立将作为双重任务干扰研究的基础，该研究将在不受指令或任务需求影响的条件下测试与双重任务成本相关的大脑活动。回答选择感兴趣区的活动将与练习中的绩效改善负相关的假设将得到严格的检验。 还将进行功能磁共振计时研究，以确定能力有限的过程是否对应于一次只能处理一个响应选择的连续瓶颈，或者它是否可以同时处理两个任务，但在这些任务之间分配资源(分级共享模式)。 最后，鉴于最近发现知觉和反应加工需求是相互作用的，功能磁共振成像研究将探讨是否存在单一的通用能力限制过程或不同但相互作用的知觉和反应能力限制。此外，这个项目将通过确定我们不能同时做一项以上的任务来调查反应选择需求如何影响知觉，是否会影响我们的视觉皮质“看”的能力。

DESCRIPTION (provided by applicant): Humans exhibit severe capacity limits: one can hardly keep in mind more than 3 or 4 items, or perform more than one task at a time. The goal of this research proposal is to develop using neuroimaging tools an understanding of the central mechanisms that limit our ability to multi-task. Since dual-tasking interference results from the failure of two sensori-motor channels to process information independently, this research will map out the neural flow of information in sensorimotor tasks that do not overlap in either sensory input or motor output. Other studies will specifically target the stage of response selection along this information pathway since it is the cognitive process most often associated with dual-task limitation. Novel fMRI chronometric approaches will be used to isolate brain regions involved in response selection, and to determine their role along the information pathway. In addition, these studies will assess whether there are both task-specific and general-purpose response-selection substrates. The establishment of the neural information pathways will serve as the groundwork for the dual-task interference studies, which will test for brain activity correlated with dual-task costs under conditions that are not affected by instructions or task demands. The hypothesis that activity in response selection ROIs will be negatively correlated with performance improvement during practice will be rigorously tested. fMRI chronometric studies will also be carded out to determine whether the capacity-limited process corresponds to a serial bottleneck that can only process one response selection at a time, or whether it can process two tasks simultaneously but divides the resources between these tasks (graded sharing model). Finally, given recent findings that perceptual and response processing demands interact, fMRI studies will address whether there is a single general-purpose capacity limited process or distinct but interacting perceptual and response capacity limits. In addition, this project will investigate how response selection demands affect perception by determining whether our inability at doing more than one task at a time affects our visual cortex ability to "see".