Ictal high frequency oscillations distinguish two types of seizure territories in humans
Ictal high frequency oscillations distinguish two types of seizure territories in humans
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DOI：
10.1093/brain/awt276
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发表时间：
2013-12-01
期刊：
影响因子：
14.5
通讯作者：
Schevon, Catherine A.
中科院分区：
文献类型：
--
作者：
Weiss, Shennan A.;Banks, Garrett P.;Schevon, Catherine A.
高频振荡已被提出作为临床上有用的生物标志物的癫痫发作产生的网站。我们使用了一套独特的人类微电极阵列记录（4例患者，10次癫痫发作），其中传播的癫痫发作波前可以很容易地识别，调查的基础上发作的高频活动在皮层（硬膜下）表面。高伽马（80-150 Hz）振幅的持续、重复性瞬时增加，相位锁定至低频（1-25 Hz）发作节律，与癫痫发作核心区域同步的强多单位放电爆发相关。这些重复的高频振荡出现在记录从硬膜下电极相邻的微电极阵列几秒钟后，癫痫发作发作，发作波阵面通道。相反，微电极记录表明，只有低水平，异质性神经放电与缺乏高频振荡在相邻的硬膜下记录网站，尽管存在一个强大的低频签名。以前，我们报告说，这种模式表明，由于前馈抑制否决机制，癫痫发作入侵该地区的失败。由于多单位放电率和高伽马振幅密切相关，因此高频振荡可用作替代标记，以区分核心癫痫发作区域与周围半影区。我们开发了一种有效的措施来检测延迟发作，持续发作的高频振荡的基础上交叉频率耦合高伽玛振幅和低频（1-25 Hz）发作节律。当应用于更广泛的硬膜下记录时，该测量一致地预测了发作侵袭的时间或失败，并揭示了一个令人惊讶的小而缓慢扩散的癫痫发作核心，周围环绕着一个更大的半影区域。因此，我们的研究结果建立了一个潜在的神经机制，延迟发病，持续发作的高频振荡，并提供了一个实用的，有效的方法，使用它们来识别小发作的核心区域。我们的观察结果表明，它可能会大大减少癫痫手术过程中皮质切除的程度，而不影响癫痫发作的控制。
High frequency oscillations have been proposed as a clinically useful biomarker of seizure generating sites. We used a unique set of human microelectrode array recordings (four patients, 10 seizures), in which propagating seizure wavefronts could be readily identified, to investigate the basis of ictal high frequency activity at the cortical (subdural) surface. Sustained, repetitive transient increases in high gamma (80-150 Hz) amplitude, phase-locked to the low-frequency (1-25 Hz) ictal rhythm, correlated with strong multi-unit firing bursts synchronized across the core territory of the seizure. These repetitive high frequency oscillations were seen in recordings from subdural electrodes adjacent to the microelectrode array several seconds after seizure onset, following ictal wavefront passage. Conversely, microelectrode recordings demonstrating only low-level, heterogeneous neural firing correlated with a lack of high frequency oscillations in adjacent subdural recording sites, despite the presence of a strong low-frequency signature. Previously, we reported that this pattern indicates a failure of the seizure to invade the area, because of a feedforward inhibitory veto mechanism. Because multi-unit firing rate and high gamma amplitude are closely related, high frequency oscillations can be used as a surrogate marker to distinguish the core seizure territory from the surrounding penumbra. We developed an efficient measure to detect delayed-onset, sustained ictal high frequency oscillations based on cross-frequency coupling between high gamma amplitude and the low-frequency (1-25 Hz) ictal rhythm. When applied to the broader subdural recording, this measure consistently predicted the timing or failure of ictal invasion, and revealed a surprisingly small and slowly spreading seizure core surrounded by a far larger penumbral territory. Our findings thus establish an underlying neural mechanism for delayed-onset, sustained ictal high frequency oscillations, and provide a practical, efficient method for using them to identify the small ictal core regions. Our observations suggest that it may be possible to reduce substantially the extent of cortical resections in epilepsy surgery procedures without compromising seizure control.