The neural bases of task proficiency and dual-tasking: Escaping the frontal bottleneck

人类认知能力最令人印象深刻的方面之一是，它有能力通过练习，将费力的任务转化为不费力就能完成的任务，甚至可以与其他需要注意力的任务并行进行。随着科技的不断发展，我们的文化中越来越多的人参与其中，多任务处理变得越来越普遍，这也带来了新的政策挑战，因为人们尝试多任务处理的能力超出了他们的认知能力，比如开车时发短信。因此，更好地了解大脑在自动化任务方面的能力和局限性是非常可取的。然而，人们对自动性和多任务处理的神经基础仍然知之甚少，这导致了对大脑多任务处理能力的重大分歧。特别是，虽然人们普遍认为学习新任务与大脑前部的任务选择回路的发展有关，该回路根据个人的注意力焦点被选择性地激活或抑制，但一些实验表明，当需要同时执行多个任务时，这种结构可能会造成认知“瓶颈”。乔治城大学（Georgetown University）的马克西米利安·里森胡伯（Maximilian Riesenhuber）博士和他的团队正在测试一个关键假设，即在某些条件下，熟悉的任务可以“卸载”给大脑后部的回路，从而释放额叶系统，同时执行额外的、需要注意力的任务。为了验证这一假设，该项目将使用复杂的行为训练范式，使参与者能够并行执行多个任务，然后结合使用先进的功能磁共振成像（fMRI）和脑电图（EEG）技术来跟踪大脑如何学习实现多任务处理。这项研究将促进我们对大脑自动化和并行任务执行能力的潜在机制的理解，这对于面对当今文化中日益增加的多任务压力至关重要。研究结果也将与一系列社会和医疗挑战相关。例如，多任务处理和任务转换的缺陷与精神分裂症和注意缺陷多动障碍有关。此外，人们越来越认识到，自动性本身可能与负面后果有关，因为由于缺乏有意识的意识和控制的减少，自动过程会降低反应的灵活性。例如，治疗药物成瘾的一个挑战是，许多与药物滥用有关的适应不良行为变得自动化。即使与高性能相关，自动任务执行也可能在问责制至关重要的领域（例如法律或医疗决策）中出现问题。了解大脑如何自动完成任务是在这些领域取得进展的关键垫脚石。

One of the most impressive aspects of human cognition is its ability to, through practice, convert effortful tasks to those that can be performed with little effort, and even in parallel with other, attention-demanding tasks. The recent proliferation of technologies permitting constant engagement in our culture has made multitasking increasingly prevalent, giving rise to new policy challenges as people's attempts at multitasking exceed their cognitive capabilities, such as when texting while driving. A better understanding of the brain's capabilities and limitations to automate tasks is therefore highly desirable. Yet, the neural bases of automaticity and multitasking are still poorly understood, leading to substantial disagreement about the brain's multitasking capabilities. In particular, while there is broad consensus that learning new tasks is associated with the development of task-selective circuits in the front of the brain which are selectively activated or suppressed depending on the individual's attentional focus, several experiments have shown that this architecture can create a cognitive "bottleneck" in situations when more than one task needs to be executed at the same time. Dr. Maximilian Riesenhuber and his team at Georgetown University are testing the key hypothesis that under certain conditions, familiar tasks can be "offloaded" to circuits in the back of the brain, thus freeing up the frontal system to simultaneously perform additional, attention-demanding tasks. To test this hypothesis, the project will use sophisticated behavioral training paradigms to enable participants to perform more than one task in parallel, and then use a combination of advanced functional magnetic resonance imaging (fMRI) and electroencephalographic (EEG) techniques to track how the brain learns to enable multitasking. The study will advance our understanding of the mechanisms underlying the brain's ability to automatize and parallelize task execution, essential in the face of the increasing pressures to multitask in today's culture. The results will also be relevant for a range of societal and medical challenges. For instance, deficits in multitasking and task switching have been associated with schizophrenia and attention deficit hyperactivity disorder. In addition, it is being increasingly appreciated that automaticity itself can be associated with negative consequences, as automatic processes can reduce flexibility in responding due to a lack of conscious awareness and decreased control. For instance, a challenge in treating drug addiction is that many maladaptive behaviors associated with drug abuse become automatized. Even when associated with high performance, automatic task execution can be problematic in domains in which accountability is critical, such as in legal or medical decision-making. Understanding how the brain automatizes tasks is a key stepping stone in making progress in these areas.