Pinault Didier
Laboratoire D'anatomo-électrophysiologie Cellulaire et Intégrée, INSERM U398, Neurobiologie et Neuropharmacologie des Epilepsies Généralisées, Faculté de Médecine, 11 rue Humann, F-67085 Strasbourg, France.
J Physiol. 2003 Nov 1;552(Pt 3):881-905. doi: 10.1113/jphysiol.2003.046573. Epub 2003 Aug 15.
In Genetic Absence Epilepsy Rats from Strasbourg (GAERS), generalized spike-and-wave (SW) discharges (5-9 SW s(-1)) develop during quiet immobile wakefulness from a natural, medium-voltage, 5-9 Hz rhythm. This study examines the spatio-temporal dynamics of cellular interactions in the somatosensory thalamocortical system underlying the generation of normal and epileptic 5-9 Hz oscillations. Paired single-unit and multi-unit recordings between the principal elements of this circuit and intracellular recordings of thalamic, relay and reticular, neurones were conducted in neuroleptanalgesied GAERS and control, non-epileptic, rats. The identity of the recorded neurones was established following juxtacellular or intracellular marking. At least six major findings have emerged from this study. (1) In GAERS, generalized spike-and-wave discharges were correlated with synchronous rhythmic firings in related thalamic relay and reticular neurones. (2) Usually, corticothalamic discharges phase-led related relay and reticular firings. (3) A depolarizing wave emerging from a barrage of EPSPs was the cause of both relay and reticular discharges. (4) In some relay cells, which had a relatively high membrane input resistance, the depolarizing wave had the shape of a ramp, which could trigger a low-threshold Ca2+ spike. (5) In reticular cells, the EPSP barrage could further trigger voltage-dependent depolarizations. (6) The epilepsy-related thalamic, relay and reticular, intracellular activities were similar to the normal-related thalamic activities. Overall, these findings strongly suggest that, during absence seizures, corticothalamic neurones play a primary role in the synchronized excitation of thalamic relay and reticular neurones. The present study further suggests that absence-related spike-and-wave discharges correspond to hypersynchronous wake-related physiological oscillations.
在来自斯特拉斯堡的遗传性失神癫痫大鼠（GAERS）中，全身性棘波-慢波（SW）放电（5 - 9次SW s⁻¹）在安静不动的清醒状态下，由一种自然的、中电压、5 - 9 Hz节律发展而来。本研究考察了体感丘脑皮质系统中细胞相互作用的时空动态，该系统是正常和癫痫性5 - 9 Hz振荡产生的基础。在接受神经安定镇痛的GAERS大鼠和对照非癫痫大鼠中，对该回路主要元件之间进行配对单单位和多单位记录，并对丘脑、中继和网状神经元进行细胞内记录。通过近细胞或细胞内标记确定所记录神经元的身份。本研究至少得出了六个主要发现。（1）在GAERS中，全身性棘波-慢波放电与相关丘脑中继和网状神经元的同步节律性放电相关。（2）通常，皮质丘脑放电在相位上领先于相关的中继和网状放电。（3）一连串兴奋性突触后电位（EPSP）产生的去极化波是中继和网状放电的原因。（4）在一些膜输入电阻相对较高的中继细胞中，去极化波呈斜坡形状，可触发低阈值Ca²⁺尖峰。（5）在网状细胞中，EPSP群可进一步触发电压依赖性去极化。（6）与癫痫相关的丘脑、中继和网状细胞内活动与正常相关的丘脑活动相似。总体而言，这些发现强烈表明，在失神发作期间，皮质丘脑神经元在丘脑中继和网状神经元的同步兴奋中起主要作用。本研究进一步表明，与失神相关的棘波-慢波放电对应于超同步的与清醒相关的生理振荡。
