Is a Cortical Spike Discharge “Transferred” to the Contralateral Cortex via the Corpus Callosum?: An Intraoperative Observation of Electrocorticogram and Callosal Compound Action Potentials

• DOI: 10.1046/j.1528-1157.2002.13402.x
• Publication Date: 2003-03-11T20:00:05Z
• Authors: Tomonori Ono; Atsuko Matsuo; Hiroshi Baba; Kenji Ono
• Keywords: Corpus callosotomy

Summary: Purpose: By means of the intraoperative electrophysiologic observation, we reevaluated “transfer” theory that a transcallosal volley invoked by cortical spike discharge in one hemisphere directly causes its contralateral counterpart via corpus callosum (CC). Methods: Twenty‐six patients who underwent callosotomy were subjects this study. Intraoperatively, electrocorticograms from both hemispheres simultaneously monitored with callosal compound action potentials (CCAPs) CC. Analysis was conducted on (a) interhemispheric delay bilaterally synchronous spike‐and‐wave discharges (BSSWs), and (b) chronological relation between BSSWs CCAPs. Results: The side prior never fixed but occasionally reversed. Interhemispheric delays not constant, regardless direction, fluctuated all patients. Most distributed within 20 ms mode 0 ms. waveform CCAP characterized slow‐rising negative potential change attained peak after discharge. These findings identical whether changed or unchanged callosotomy. Conclusions: If role CC is true, must be longer than axonal conduction time (about ms), preceding produce then order time. However, hypothesis confirmed present We propose recruitment epileptogenic state as different epileptogenesis.