Preparation and control of rapid voluntary movements

想象两个截然不同但现实生活中的场景。在第一起案件中，一名开着巡逻车的警察拦下了一辆疑似被盗车辆。警官拔出枪，走到被盗车辆的驾驶员一侧。当他走近司机时，一辆跟在警察后面的车“走火”了。警官向被盗车辆开枪，打伤了嫌疑人。这名警官有没有故意向嫌疑人开枪？在第二种情况下，奥运会田径100米决赛正在进行中，这位世界纪录保持者在之前一次发车失误后，正处于发令员的命令之下。发令枪响了，运动员从拦网中“爆炸”出来，大多数人认为这是一个良好的开端。然而，他创造了一个力量的增加，记录在发令枪发射后96毫秒的“起跑块”上。国际田径联合会表示，任何运动员在发车信号发出后，在100毫秒之前加大“拦网”的力量，都必须是“抢跑”。因此，这名运动员被取消了比赛资格。这位运动员是不是故意在没有等待发令枪响的情况下提前发车？这两种情况有关联吗？警察和运动员的行为都可以解释吗？很明显，人们每天都需要对日常刺激做出快速反应，长期以来，人们一直认为这些运动是通过通过高级大脑中枢(皮质环)的信息流来控制的。然而，我们最近(与其他人一起)表明，当准备好的反应准备好进行时，响亮的信号具有惊吓个体的效果，导致整个反应被释放，在某些情况下，受试者没有意识到反应已经发生。我们已经观察到对意外的令人震惊的刺激的反应时间低至65ms。我们的假设是，准备好的反应是预先编程的，并存储在较低的(皮质下)大脑结构中。当信号到达时，反应会被令人震惊的声音提前触发，绕过皮层处理，导致反应时间缩短。我提议的研究方案将调查负责这种快速准备行动的过程，并阐明其准备、储存和执行情况。

Picture two very different but real life scenarios. In the first a policeman in a patrol car pulls over a suspected stolen vehicle. The officer draws his gun and walks over to the driver side of the stolen vehicle. As he approaches the driver a car that is driving behind the policeman "backfires". The officer discharges his weapon into the stolen vehicle injuring the suspect. Did the officer intentionally fire his gun at the suspect? In the second scenario an Olympic track and field 100m final is underway and the world record holder is "under starter's orders" after having false started once before. The starter pistol is fired and the athlete "explodes" out of the blocks for what most believe to be a good start. However, he has produced an increase in force that is recorded on the "starting blocks" 96 ms after the starter pistol fired. The International Association of Athletics Federation state that any athlete increasing force on the "blocks" before 100 ms has passed after the starter signal must have "jumped the gun". Therefore the athlete was disqualified. Did the athlete intentionally anticipate the start without waiting for the sound of the starter pistol? Are these two scenarios related and can the actions of both the policeman and the athlete be explained? It is clear that fast responses to everyday stimuli are required of people on a daily basis and these movements have long been thought to be controlled via information flow through higher brain centres (cortical loops). However, we have recently shown (along with others) that when the prepared response is ready to go the loud signal has the effect of startling the individual causing the entire response to be released, in some instances without the subject being aware that the response has occurred. We have observed reaction times to unanticipated startling stimuli as low as 65 ms. Our hypothesis is that a prepared response is pre-programmed and stored in lower (subcortical) brain structures. When the signal arrives the response is triggered early by the startling sound, bypassing cortical processing and resulting in short reaction times. The programme of research that I propose will investigate the processes responsible for such fast prepared actions and shed light on their preparation, storage and execution.