Guthrie Michael D, Gilbert Donald L, Huddleston David A, Pedapati Ernest V, Horn Paul S, Mostofsky Stewart H, Wu Steve W
College of Medicine, University of Cincinnati.
Division of Neurology, Cincinnati Children's Hospital Medical Center.
J Vis Exp. 2018 Feb 8(132):56789. doi: 10.3791/56789.
We describe the development of a reproducible, child-friendly motor response inhibition task suitable for online Transcranial Magnetic Stimulation (TMS) characterization of primary motor cortex (M1) excitability and inhibition. Motor response inhibition prevents unwanted actions and is abnormal in several neuropsychiatric conditions. TMS is a non-invasive technology that can quantify M1 excitability and inhibition using single- and paired-pulse protocols and can be precisely timed to study cortical physiology with high temporal resolution. We modified the original Slater-Hammel (S-H) stop signal task to create a "racecar" version with TMS pulses time-locked to intra-trial events. This task is self-paced, with each trial initiating after a button push to move the racecar towards the 800 ms target. GO trials require a finger-lift to stop the racecar just before this target. Interspersed randomly are STOP trials (25%) during which the dynamically adjusted stop signal prompts subjects to prevent finger-lift. For GO trials, TMS pulses were delivered at 650 ms after trial onset; whereas, for STOP trials, the TMS pulses occurred 150 ms after the stop signal. The timings of the TMS pulses were decided based on electroencephalography (EEG) studies showing event-related changes in these time ranges during stop signal tasks. This task was studied in 3 blocks at two study sites (n=38) and we recorded behavioral performance and event-related motor-evoked potentials (MEP). Regression modelling was used to analyze MEP amplitudes using age as a covariate with multiple independent variables (sex, study site, block, TMS pulse condition [single- vs. paired-pulse], trial condition [GO, successful STOP, failed STOP]). The analysis showed that TMS pulse condition (p<0.0001) and its interaction with trial condition (p=0.009) were significant. Future applications for this online S-H/TMS paradigm include the addition of simultaneous EEG acquisition to measure TMS-evoked EEG potentials. A potential limitation is that in children, the TMS pulse sound could affect behavioral task performance.
我们描述了一种可重复、适合儿童的运动反应抑制任务的开发，该任务适用于对初级运动皮层（M1）兴奋性和抑制进行在线经颅磁刺激（TMS）表征。运动反应抑制可防止不必要的动作，并且在几种神经精神疾病中存在异常。TMS是一种非侵入性技术，可使用单脉冲和双脉冲方案量化M1的兴奋性和抑制，并且可以精确计时以高时间分辨率研究皮层生理学。我们修改了原始的斯莱特 - 哈默尔（S - H）停止信号任务，创建了一个“赛车”版本，其中TMS脉冲与试验内事件进行时间锁定。此任务是自定节奏的，每次试验在按下按钮后启动，将赛车驶向800毫秒的目标。“执行”试验要求在到达该目标之前抬起手指以停止赛车。随机穿插“停止”试验（25%），在此期间动态调整的停止信号提示受试者防止抬起手指。对于“执行”试验，TMS脉冲在试验开始后650毫秒发放；而对于“停止”试验，TMS脉冲在停止信号后150毫秒发放。TMS脉冲的时间是根据脑电图（EEG）研究确定的，这些研究表明在停止信号任务期间这些时间范围内存在与事件相关的变化。在两个研究地点对38名受试者进行了3个组块的该任务研究，我们记录了行为表现和与事件相关的运动诱发电位（MEP）。使用回归模型分析MEP幅度，将年龄作为协变量，纳入多个自变量（性别、研究地点、组块、TMS脉冲条件[单脉冲与双脉冲]、试验条件[执行、成功停止、失败停止]）。分析表明，TMS脉冲条件（p<0.0001）及其与试验条件的相互作用（p = 0.009）具有显著性。这种在线S - H/TMS范式的未来应用包括增加同步EEG采集以测量TMS诱发的EEG电位。一个潜在的限制是在儿童中，TMS脉冲声音可能会影响行为任务表现。
