Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
Department of Psychology, New York University, New York, NY 10012, USA.
Cereb Cortex. 2018 Jan 1;28(1):9-20. doi: 10.1093/cercor/bhw343.
Electrophysiology and neuroimaging provide conflicting evidence for the neural contributions to target detection. Scalp electroencephalography (EEG) studies localize the P3b event-related potential component mainly to parietal cortex, whereas neuroimaging studies report activations in both frontal and parietal cortices. We addressed this discrepancy by examining the sources that generate the target-detection process using electrocorticography (ECoG). We recorded ECoG activity from cortex in 14 patients undergoing epilepsy monitoring, as they performed an auditory or visual target-detection task. We examined target-related responses in 2 domains: high frequency band (HFB) activity and the P3b. Across tasks, we observed a greater proportion of electrodes that showed target-specific HFB power relative to P3b over frontal cortex, but their proportions over parietal cortex were comparable. Notably, there was minimal overlap in the electrodes that showed target-specific HFB and P3b activity. These results revealed that the target-detection process is characterized by at least 2 different neural markers with distinct cortical distributions. Our findings suggest that separate neural mechanisms are driving the differential patterns of activity observed in scalp EEG and neuroimaging studies, with the P3b reflecting EEG findings and HFB activity reflecting neuroimaging findings, highlighting the notion that target detection is not a unitary phenomenon.
电生理学和神经影像学为目标检测的神经贡献提供了相互矛盾的证据。头皮脑电图（EEG）研究将 P3b 事件相关电位成分主要定位在顶叶皮层，而神经影像学研究则报告在额叶和顶叶皮层都有激活。我们通过使用皮层脑电图（ECoG）检查产生目标检测过程的源来解决这一差异。我们在 14 名接受癫痫监测的患者中记录了 ECoG 活动，他们在执行听觉或视觉目标检测任务时进行了记录。我们在 2 个领域检查了与目标相关的反应：高频带（HFB）活动和 P3b。在所有任务中，我们发现相对于 P3b，额叶皮层上显示目标特异性 HFB 功率的电极比例更大，但在顶叶皮层上的比例相当。值得注意的是，显示目标特异性 HFB 和 P3b 活动的电极之间几乎没有重叠。这些结果表明，目标检测过程的特征是至少有 2 种不同的神经标记，具有不同的皮质分布。我们的发现表明，不同的神经机制驱动着头皮 EEG 和神经影像学研究中观察到的不同活动模式，P3b 反映了 EEG 研究结果，HFB 活动反映了神经影像学研究结果，这突出了目标检测不是一个单一现象的观点。
