Epilepsy Center, University Medical Center Freiburg, Freiburg, Germany; Neurobiology and Biophysics, Faculty of Biology, University of Freiburg, Freiburg, Germany.
Epilepsy Center, University Medical Center Freiburg, Freiburg, Germany; Hermann Paul School of Linguistics, Freiburg, Germany.
Neuroimage. 2013 Nov 1;81:164-177. doi: 10.1016/j.neuroimage.2013.04.102. Epub 2013 May 3.
Precise delineation of pathological and eloquent cortices is essential in pre-neurosurgical diagnostics of epilepsy. A limitation of existing experimental procedures, however, is that they critically require active cooperation of the patient, which is not always achievable, particularly in infants and in patients with insufficient cognitive abilities. In the present study, we evaluated the potential of electrocorticographic recordings of high gamma activity during natural, non-experimental behavior of epilepsy patients to localize upper- and lower-extremity motor and language functions, and compared the results with those obtained using electrocortical stimulation. The observed effects were highly significant and functionally specific, and agreed well with the somatotopic organization of the motor cortex, both on the lateral convexity and in the supplementary motor area. Our approach showed a similar specificity and sensitivity for extremity movements as previously obtained from experimental data. We were able to quantify, for the first time, sensitivity and specificity of high gamma underlying non-experimental lower-extremity movements in four patients, and observed values in the same range as for upper extremities (analyzed in six patients). Speech-related responses in the three investigated patients, however, exhibited only a very low sensitivity. The present findings indicate that localization of not only upper- but also lower-extremity movements congruent with electrocortical stimulation mapping is possible based on event-related high gamma responses that can be observed during natural behavior. Thus, non-experimental mapping may be usefully applied as adjunct to established clinical procedures for identification of both upper- and lower-extremity motor functions.
在癫痫的神经外科术前诊断中，精确划定病理和功能区皮质至关重要。然而，现有实验程序的一个局限性是，它们严重依赖于患者的积极配合，而这在某些情况下是无法实现的，尤其是在婴儿和认知能力不足的患者中。在本研究中，我们评估了癫痫患者在自然非实验行为期间记录高γ活动的脑电图记录来定位上肢和下肢运动及语言功能的潜力，并将结果与电刺激的结果进行了比较。观察到的效应具有高度的显著性和功能特异性，与运动皮质的躯体定位组织非常吻合，无论是在外侧凸面还是在辅助运动区。我们的方法在定位上肢运动方面的特异性和敏感性与之前从实验数据中获得的结果相似。我们首次能够在四名患者中量化非实验性下肢运动的高γ下的敏感性和特异性，并观察到与上肢（在六名患者中分析）相同范围内的值。然而，在三名被调查患者中，与言语相关的反应仅表现出非常低的敏感性。本研究结果表明，不仅可以基于在自然行为中观察到的与电刺激映射一致的事件相关高γ反应来定位上肢运动，还可以定位下肢运动。因此，非实验性映射可以作为识别上肢和下肢运动功能的既定临床程序的辅助手段。
