Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.
Magn Reson Med. 2010 Oct;64(4):1191-9. doi: 10.1002/mrm.22508.
Simultaneous electrophysiological and functional magnetic resonance imaging measurements of animal models of epilepsy are methodologically challenging, but essential to better understand abnormal brain activity and hemodynamics during seizures. In this study, functional magnetic resonance imaging of medetomidine-sedated rats was performed using novel rapid acquisition by sequential excitation and refocusing (RASER) fast imaging pulse sequence and simultaneous local field potential measurements during kainic acid-induced seizures. The image distortion caused by the hippocampal-measuring electrode was clearly seen in echo planar imaging images, whereas no artifact was seen in RASER images. Robust blood oxygenation level-dependent responses were observed in the hippocampus during kainic acid-induced seizures. The recurrent epileptic seizures were detected in the local field potential signal after kainic acid injection. The presented combination of deep electrode local field potential measurements and functional magnetic resonance imaging under medetomidine anesthesia, which does not significantly suppress kainic acid-induced seizures, provides a unique tool for studying abnormal brain activity in rats.
对癫痫动物模型进行同时电生理和功能磁共振成像测量在方法学上具有挑战性，但对于更好地理解癫痫发作期间的异常脑活动和血液动力学至关重要。在这项研究中，使用新型快速采集序列激发和重聚焦（RASER）快速成像脉冲序列对美托咪定镇静大鼠进行功能磁共振成像，并在海人酸诱导的癫痫发作期间进行同时局部场电位测量。在磁共振成像图像中可以清楚地看到由海马测量电极引起的图像失真，而在 RASER 图像中则没有伪影。在海人酸诱导的癫痫发作期间，在海马体中观察到了强大的血氧水平依赖反应。在海人酸注射后，局部场电位信号中检测到复发性癫痫发作。本研究在美托咪定麻醉下将深部电极局部场电位测量和功能磁共振成像相结合，这种方法不会显著抑制海人酸诱导的癫痫发作，为研究大鼠异常脑活动提供了一种独特的工具。
