Fabó Dániel, Maglóczky Zsófia, Wittner Lucia, Pék Agnes, Eross Loránd, Czirják Sándor, Vajda János, Sólyom András, Rásonyi György, Szucs Anna, Kelemen Anna, Juhos Vera, Grand László, Dombovári Balázs, Halász Péter, Freund Tamás F, Halgren Eric, Karmos György, Ulbert István
Institute for Psychology, Hungarian Academy of Sciences, 1068 Budapest, Szondi u. 83-85, Hungary.
Brain. 2008 Feb;131(Pt 2):485-99. doi: 10.1093/brain/awm297. Epub 2007 Dec 14.
A large proportion of hippocampal afferents and efferents are relayed through the subiculum. It is also thought to be a key structure in the generation and maintenance of epileptic activity; rhythmic interictal-like discharges were recorded in previous studies of subicular slices excised from temporal lobe epilepsy patients. In order to investigate if and how the subiculum is involved in the generation of epileptic discharges in vivo, subicular and lateral temporal lobe electrical activity were recorded under anesthesia in 11 drug-resistant epilepsy patients undergoing temporal lobectomy. Based on laminar field potential gradient, current source density, multiple unit activity (MUA) and spectral analyses, two types of interictal spikes were distinguished in the subiculum. The more frequently occurring spike started with an initial excitatory current (current source density sink) in the pyramidal cell layer associated with increased MUA in the same location, followed by later inhibitory currents (current source density source) and decreased MUA. In the other spike type, the initial excitation was confined to the apical dendritic region and it was associated with a less-prominent increase in MUA. Interictal spikes were highly synchronized at spatially distinct locations of the subiculum. Laminar data showed that the peak of the initial excitation occurred within 0-4 ms at subicular sites separated by 6 mm at the anterior-posterior axis. In addition, initial spike peak amplitudes were highly correlated in most recordings. A subset of subicular and temporal lobe spikes were also highly synchronous, in one case the subicular spikes reliably preceded the temporal lobe discharges. Our results indicate that multiple spike generator mechanisms exist in the human epileptic subiculum suggesting a complex network interplay between medial and lateral temporal structures during interictal epileptic activity. The observed widespread intra-subicular synchrony may reflect both of its intrinsic and extrinsically triggered activity supporting the hypothesis that subiculum may also play an active role in the distribution of epileptiform activity to other brain regions. Limited data suggest that subiculum might even play a pacemaker role in the generation of paroxysmal discharges.
很大一部分海马体传入神经和传出神经是通过下托中继的。它也被认为是癫痫活动产生和维持的关键结构；在先前对从颞叶癫痫患者切除的下托切片的研究中记录到了节律性发作间期样放电。为了研究下托是否以及如何参与体内癫痫放电的产生，在11例接受颞叶切除术的耐药癫痫患者麻醉状态下记录了下托和颞叶外侧的电活动。基于层流场电位梯度、电流源密度、多单位活动（MUA）和频谱分析，在下托中区分出两种类型的发作间期棘波。较频繁出现的棘波始于锥体细胞层的初始兴奋性电流（电流源密度下沉），同时同一位置的MUA增加，随后是后期抑制性电流（电流源密度源）和MUA降低。在另一种棘波类型中，初始兴奋局限于顶端树突区域，且与MUA不太明显的增加相关。发作间期棘波在下托的空间不同位置高度同步。层流数据显示，初始兴奋的峰值出现在前后轴相距6mm的下托部位的0 - 4ms内。此外，在大多数记录中，初始棘波峰值幅度高度相关。下托和颞叶棘波的一个子集也高度同步，在一个病例中，下托棘波可靠地先于颞叶放电。我们的结果表明，人类癫痫下托中存在多种棘波产生机制，提示在发作间期癫痫活动期间内侧和外侧颞叶结构之间存在复杂的网络相互作用。观察到的下托内广泛同步可能反映了其内在和外在触发的活动，支持下托可能在癫痫样活动向其他脑区的传播中也发挥积极作用的假设。有限的数据表明，下托甚至可能在阵发性放电的产生中起起搏器作用。
