Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy.
Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy.
Exp Neurol. 2019 Nov;321:113014. doi: 10.1016/j.expneurol.2019.113014. Epub 2019 Jul 16.
The piriform cortex is recognized to play critical roles in focal ictogenesis, both in animal models and in humans. We review here the contribution of in vitro studies performed on rodent brain tissue that were aimed at understanding the ictogenic properties of the piriform cortex and the contiguous olfactory areas. During in vitro experiments, epileptiform events can be easily generated in the piriform area by diverse pro-convulsive drugs (4-aminopyridine, bicuculline, picrotoxin) or by electrical stimulation. Simultaneous intracellular and field potential recordings performed on in vitro preparations, which include brain slices of rats and mice and the isolated brains of guinea pigs, demonstrated that both the piriform cortex proper and the endopiriform nucleus (also considered part of the piriform area) generate interictal spikes, high-frequency oscillations and seizure-like activities that mimic focal discharges. These findings were confirmed both by optical recordings of intrinsic signals coupled with brain activity and by fast imaging of optical signals generated by voltage-sensitive dyes. Overall, these studies demonstrated that epileptiform discharges effectively propagate from the piriform structures to the limbic regions, supporting the conditions for secondarily generalized ictogenesis.
梨状皮层被认为在局灶性癫痫发作的发生中起着关键作用，无论是在动物模型还是在人类中。我们在这里回顾了在啮齿动物脑组织上进行的体外研究的贡献，这些研究旨在了解梨状皮层和相邻嗅觉区的致痫特性。在体外实验中，多种促惊厥药物（4-氨基吡啶、荷包牡丹碱、印防己毒素）或电刺激可轻易在梨状区产生癫痫样事件。在包括大鼠和小鼠脑片以及豚鼠离体脑的体外标本上进行的细胞内和场电位同时记录表明，梨状皮层和内嗅核（也被认为是梨状区的一部分）都产生棘波、高频振荡和类似局灶性放电的癫痫样活动。这些发现得到了结合脑活动的内在信号的光学记录以及通过电压敏感染料产生的光信号的快速成像的证实。总的来说，这些研究表明，癫痫样放电有效地从梨状结构传播到边缘区域，为继发性全身性癫痫发作的发生创造了条件。
