Lesser Ronald P, Webber W R S, Miglioretti Diana L, Mizuno-Matsumoto Yuko, Muramatsu Ayumi, Yamamoto Yusuke
Departments of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
Neurological Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
Front Hum Neurosci. 2021 Jan 22;14:609188. doi: 10.3389/fnhum.2020.609188. eCollection 2020.
Cortical stimulation has been used for brain mapping for over a century, and a standard assumption is that stimulation interferes with task execution due to local effects at the stimulation site. Stimulation can however produce afterdischarges which interfere with functional localization and can lead to unwanted seizures. We previously showed that (a) cognitive effort can terminate these afterdischarges, (b) when termination thus occurs, there are electrocorticography changes throughout the cortex, not just at sites with afterdischarges or sites thought functionally important for the cognitive task used, and (c) thresholds for afterdischarges and functional responses can change among stimulation trials. We here show that afterdischarge termination can occur prior to overt performance of the cognitive tasks used to terminate them. These findings, taken together, demonstrate that task-related brain changes are not limited to one or a group of functional regions or a specific network, and not limited to the time directly surrounding overt task execution. Discrete locations, networks and times importantly underpin clinical behaviors. However, brain activity that is diffuse in location and extended in time also affect task execution and can affect brain mapping. This may in part reflect fluctuating levels of attention, engagement, or motivation during testing.
皮层刺激用于脑图谱绘制已有一个多世纪，一个标准的假设是，刺激会由于刺激部位的局部效应而干扰任务执行。然而，刺激会产生后放电，干扰功能定位并可能导致不必要的癫痫发作。我们之前表明：（a）认知努力可以终止这些后放电；（b）当终止发生时，整个皮层会出现皮层脑电图变化，而不仅仅是在后放电部位或被认为对所使用的认知任务具有功能重要性的部位；（c）后放电和功能反应的阈值在刺激试验之间可能会发生变化。我们在此表明，后放电终止可能发生在用于终止它们的认知任务的明显表现之前。综合这些发现表明，与任务相关的大脑变化不仅限于一个或一组功能区域或特定网络，也不限于直接围绕明显任务执行的时间。离散的位置、网络和时间对临床行为起着重要支撑作用。然而，位置分散且时间延长的大脑活动也会影响任务执行，并可能影响脑图谱绘制。这可能部分反映了测试期间注意力、参与度或动机水平的波动。
