Changes in Brain Signal Variability as a Function of Learning and Expertise in Lexical Decision Making

在将大脑信号与认知联系起来时，假设行为过程会激活大脑的关键区域。就像计算机一样，当需要它所支持的进程时，该区域是“开”的，而当不需要该进程时，该区域是“关”的。大脑组织的一些关键特征表明，我们需要重新思考这个想法。研究人员已经表明，大脑依赖于活动和可变性来确保最佳功能，并且大脑区域在任何时候都会产生可变的信号（即使在计算机模拟中它们是“关闭”的）。事实上，大脑信号的可变性使人们能够快速灵活地对环境需求做出反应。不要把大脑看作是一台可以开关的计算机，而要把大脑看作是一个不断运动的系统，把可变性看作是一种动能，使这个系统能够轻松地从一个网络移动到另一个网络。 是什么决定了大脑的变异性？一些科学家认为它代表了信息处理能力--本质上，它告诉我们大脑支持任务执行的能力。让大脑更有能力支持一项任务的一种方法是，通过花时间练习，学会把这项任务做得特别好。我的研究检查了学习过程中的大脑信号，同时人们练习快速做出单词和非单词的决定。我预计，在实践的早期，随着人们探索不同的快速反应方式，大脑的变异性会增加。当人们决定了最好的回应方式后，变异性会降低（但会保持比练习前更高的水平）。我还将在专业知识的背景下研究大脑的变异性。拼字游戏的竞争者是做单词和非单词决定的专家，我希望他们的大脑比非专家产生更多的可变信号来支持这项任务。在未来，这项研究计划将使科学家能够利用大脑的变异性来了解处理能力，并可能帮助人们更好地学习。

In relating brain signals to cognition, the assumption is that behavioural processes will activate key regions of the brain. Much like a computer, the region is 'on' when the process it supports is required, and 'off' when the process is not required. Some critical features of brain organization suggest that we need to rethink this idea. Researchers have shown that the brain relies on both activity and variability to ensure optimal function, and that brain regions produce variable signal at all times (even when they are 'off' in the computer analogy). In fact, brain signal variability allows people to respond quickly and flexibly to environmental demands. Instead of a computer that turns on and off, think of the brain as a system in constant motion, and think of variability as the kinetic energy that allows this system to move easily from one network to another. What determines brain variability? Some scientists suggest that it represents information processing capacity - essentially, that it tells us about the capability of a brain to support task performance. One way to make the brain more capable of supporting a task is to learn to do that task exceptionally well, by devoting time to practice. My research examines brain signal during the learning process, while people practice making quick word-nonword decisions. I expect that early in practice, brain variability will increase as people explore different ways to respond quickly. Variability will then decrease after people settle on the best way to respond (but stay higher than before practice). I will also look at brain variability in the context of expertise. Competitive Scrabble players are experts at making word-nonword decisions, and I expect their brains to produce more variable signal to support this task than non-experts. In the future, this research program will enable scientists to use brain variability to understand processing capacity, and possibly allow us to help people learn better.