Rethinking the reaction time

无论是在前方道路出现危险时踩下刹车踏板，还是响应发令员的手枪开始冲刺，还是伸手接住倾斜镜，我们都拥有快速而准确地对行动要求做出反应的非凡能力。这些反应发生在大约250毫秒的反应时间内，在此期间，我们必须感知行动的必要性，准确地决定采取什么行动，并产生运动指令来协调数十块肌肉的活动来进行运动。目前尚不清楚这一途径中的哪些步骤需要最多的时间，哪些大脑区域负责哪些计算，以及反应时间是否可以缩短得更短。在国家科学基金会的支持下，John Krakauer博士及其同事禤浩焯·海斯博士、Pablo Celnik博士和Joshua Ewan博士将在人类参与者中进行创新的行为实验，强调反应时间的限制，并梳理其组成过程和限制。他们将在这些相同的任务中记录大脑活动(使用EEG)，以确定潜在的大脑网络负责，并将应用非侵入性脑刺激来建立这些大脑网络在产生快速运动反应方面的特定功能。许多神经疾病，如帕金森病，与运动反应减慢有关。这些症状目前还没有得到很好的理解。从这项研究中获得的知识将产生关于为什么会发生这种减慢的重要见解，以及从治疗和/或临床的角度来看，可以采取什么措施来治疗它。对于那些寻求突破人类表现极限的人，比如运动员和赛车手，或者寻求提高自身表现的业余爱好者来说，更深入地了解反应时间也将是非常有意义的。此外，在这项研究中收集的数据可能会引起广泛的兴趣，因此将提供给其他研究人员。脑电记录将特别引起研究人员的兴趣，他们正在开发先进的分析技术来绘制人脑活动图。最后，来自代表性不足的少数群体的学生，包括那些经济上处于不利地位的学生，将有机会直接参与这一项目，并通过约翰·霍普金斯大学多样性暑期实习计划获得宝贵的研究经验。

Whether stepping on the brake pedal when a hazard appears in the road ahead, beginning a sprint in response to the starter's pistol, or reaching to catch a tipping glass, we possess a remarkable ability to respond rapidly and accurately to demands for action. These responses occur within a reaction time of around 250 milliseconds, during which we must perceive the need to act, decide precisely what action to take, and generate motor commands to coordinate the activity of dozens of muscles to make the movement. It is currently not clearly understood what steps in this pathway take the greatest amount of time, which brain regions are responsible for which computations, and whether or not the reaction time could be reduced even lower. With support from the National Science Foundation, Dr. John Krakauer and colleagues Dr. Adrian Haith, Dr. Pablo Celnik and Dr. Joshua Ewan will use innovative behavioral experiments with human participants to stress the limits of the reaction time and tease apart its constituent processes and limitations. They will record brain activity during these same tasks (using EEG) in order to identify the underlying brain networks responsible and will apply non-invasive brain stimulation to establish the specific function of these brain networks in generating rapid motor responses.A number of neurological disorders, such as Parkinson disease, are associated with slowing of motor responses. Such symptoms are not well-understood at present. The knowledge gained from this study will yield important insights as to why this slowing may occur and what, if anything, could be done to treat it from a therapeutic and/or clinical perspective. A deeper understanding of the reaction time will also be of significant interest to those seeking to push the limits of human performance, such as athletes and race car drivers, or amateurs seeking to better their own performance. Furthermore, data collected in this study are likely to be of broad interest and therefore will be made available to other researchers. EEG recordings will be of particular interest to researchers developing advanced analytical techniques for mapping human brain activity. Finally, students from under-represented minorities, including those from economically disadvantaged backgrounds, will have the opportunity to directly participate in this project and gain valuable research experience through the Johns Hopkins Diversity Summer Internship Program.