Ono Tomonori, Matsuo Atsuko, Baba Hiroshi, Ono Kenji
Department of Neurosurgery, Nagasaki University School of Medicine, Nagasaki, Japan.
Epilepsia. 2002 Dec;43(12):1536-42. doi: 10.1046/j.1528-1157.2002.13402.x.
By means of the intraoperative electrophysiologic observation, we reevaluated the "transfer" theory that a transcallosal volley invoked by a cortical spike discharge in one hemisphere directly causes its contralateral counterpart via the corpus callosum (CC).
Twenty-six patients who underwent corpus callosotomy were the subjects of this study. Intraoperatively, electrocorticograms from both hemispheres were simultaneously monitored with callosal compound action potentials (CCAPs) from the CC. Analysis was conducted on (a) the interhemispheric delay of bilaterally synchronous spike-and-wave discharges (BSSWs), and (b) the chronological relation between BSSWs and CCAPs.
The side of prior spike discharges was never fixed but was occasionally reversed. Interhemispheric delays between the BSSWs were not constant, regardless of direction, and fluctuated in all patients. Most of the interhemispheric delays were distributed within 20 ms with a mode of 0 ms. The waveform of the CCAP was characterized by slow-rising negative potential change that attained its peak after a cortical spike discharge. These findings were identical in all the patients regardless of whether the BSSWs were changed or unchanged after callosotomy.
If the "transfer" role of the CC is true, interhemispheric delays between BSSWs must be longer than interhemispheric axonal conduction time (about 20 ms), and a preceding cortical spike discharge must produce a CCAP and then a contralateral one in order of time. However, this hypothesis was not confirmed in the present study. We propose the interhemispheric recruitment of the epileptogenic state as a different role of the CC on epileptogenesis.
通过术中电生理观察，我们重新评估了“传递”理论，即一个半球的皮质尖峰放电引发的经胼胝体的 volley 直接通过胼胝体（CC）导致其对侧对应部位的放电。
本研究以 26 例行胼胝体切开术的患者为研究对象。术中，同时监测两个半球的皮质电图以及来自 CC 的胼胝体复合动作电位（CCAPs）。对以下内容进行分析：（a）双侧同步棘波 - 慢波放电（BSSWs）的半球间延迟，以及（b）BSSWs 与 CCAPs 之间的时间关系。
先前尖峰放电的一侧并非固定不变，而是偶尔会反转。无论方向如何，BSSWs 之间的半球间延迟并不恒定，且在所有患者中均有波动。大多数半球间延迟分布在 20 毫秒以内，众数为 0 毫秒。CCAP 的波形特征为缓慢上升的负电位变化，在皮质尖峰放电后达到峰值。无论胼胝体切开术后 BSSWs 是否改变，所有患者的这些发现均相同。
如果 CC 的“传递”作用是真实的，那么 BSSWs 之间的半球间延迟必须长于半球间轴突传导时间（约 20 毫秒），并且先前的皮质尖峰放电必须按时间顺序产生一个 CCAP，然后再产生一个对侧的 CCAP。然而，本研究并未证实这一假设。我们提出癫痫发作状态的半球间募集是 CC 在癫痫发生过程中的一种不同作用。
