Rethinking the reaction time

无论是在前方道路出现危险时踩下刹车踏板，还是在发令员开枪时开始冲刺，或者伸手抓住翻倒的玻璃杯，我们都拥有快速准确地响应行动要求的非凡能力。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需要，准确地决定采取什么行动，并产生运动命令来协调数十块肌肉的活动来进行运动。目前还不清楚这一途径中的哪些步骤需要花费最多的时间，哪些大脑区域负责哪些计算，以及反应时间是否可以减少得更低。在美国国家科学基金会的支持下，约翰·克拉考尔博士和他的同事阿德里安·海斯博士、巴勃罗·塞尔尼克博士和约书亚·尤恩博士将利用人类参与者的创新行为实验来强调反应时间的极限，并梳理其组成过程和局限性。他们将在这些相同的任务中记录大脑活动（使用EEG），以确定负责的潜在大脑网络，并将应用非侵入性大脑刺激来建立这些大脑网络在产生快速运动反应中的特定功能。许多神经系统疾病，如帕金森病，与运动反应减慢有关。这些症状目前还不清楚。从这项研究中获得的知识将产生重要的见解，为什么会发生这种减缓，以及从治疗和/或临床角度可以采取什么措施来治疗它。对反应时间的更深入了解也将对那些寻求推动人类表现极限的人产生重大兴趣，例如运动员和赛车手，或者寻求改善自己表现的业余爱好者。此外，本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。脑电图记录将特别感兴趣的研究人员开发先进的分析技术，以映射人类大脑活动。最后，来自代表性不足的少数民族的学生，包括那些来自经济上处于不利地位的背景，将有机会直接参与这个项目，并通过约翰霍普金斯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.