Bayat Arezou, Joshi Sweta, Jahan Sahar, Connell Phillip, Tsuchiya Komei, Chau David, Syed Tanvir, Forcelli Patrick, Koubeissi Mohamad Z
Department of Neurology, George Washington University, Washington, DC, 20037, USA.
Department of Neurology, University Hospitals Case Medical, Cleveland, OH, 44106, USA.
Epilepsy Res. 2018 Feb;140:97-104. doi: 10.1016/j.eplepsyres.2018.01.006. Epub 2018 Jan 5.
The claustrum has been implicated in consciousness, and MRIs of patients with status epilepticus have shown increased claustral signal intensity. In an attempt to investigate the role of claustrum in cognition and seizures, we (1) assessed the effect of high-frequency stimulation (HFS) of the claustrum on performance in the operant chamber; (2) studied interclaustral and claustrohippocampal connectivity through cerebro-cerebral evoked potentials (CCEPs); and (3) investigated the role of claustrum in kainate-induced (KA) seizures.
Adult male Sprague-Dawley rats were trained in operant conditioning and implanted with electrodes in bilateral claustra and hippocampi. Claustrum HFS (50 Hz) was delivered bilaterally and unilaterally with increasing intensities from 50 to 1000 μA, and performance scores were assessed. CCEPs were studied by averaging the responses to bipolar stimulations, 1-ms wide pulses at 0.1 Hz to the claustrum. KA seizures were analyzed on video-EEG recordings.
Generalized Estimating Equations analysis revealed that claustral stimulation reduced task performance scores relative to rest sessions (bilateral: -15.8 percentage points, p < 0.0001; unilateral: -15.2, p < 0.0001). With some stimulations, the rats showed a stimulus-locked decrease in attentiveness and, occasionally, an inability to complete the operant task. CCEPs demonstrated interclaustral and claustrohippocampal connectivity. Some KA seizures appeared to originate from the claustrum.
Findings from the operant conditioning task suggest stimulation of the claustrum can alter attention or awareness. CCEPs demonstrated connectivity between the two claustra and between the claustrum and the hippocampi. Such connectivity may be part of the circuitry that underlies the alteration of awareness in limbic seizures. Lastly, KA seizures showed early involvement of the claustrum, a finding that also supports a possible role of the claustrum in the alteration of consciousness that accompanies dyscognitive seizures.
屏状核与意识有关，癫痫持续状态患者的磁共振成像显示屏状核信号强度增加。为了研究屏状核在认知和癫痫发作中的作用，我们：（1）评估屏状核高频刺激（HFS）对操作箱内行为表现的影响；（2）通过脑-脑诱发电位（CCEP）研究屏状核间及屏状核与海马之间的连接性；（3）研究屏状核在海藻酸诱导（KA）癫痫发作中的作用。
成年雄性Sprague-Dawley大鼠接受操作条件反射训练，并在双侧屏状核和海马植入电极。双侧和单侧给予屏状核HFS（50Hz），强度从50μA增加到1000μA，并评估行为表现评分。通过对屏状核0.1Hz、1ms宽双极刺激的反应进行平均来研究CCEP。在视频脑电图记录上分析KA癫痫发作。
广义估计方程分析显示，与休息时段相比，屏状核刺激降低了任务表现评分（双侧：-15.8个百分点，p<0.0001；单侧：-15.2，p<0.0001）。在一些刺激下，大鼠表现出与刺激相关的注意力下降，偶尔无法完成操作任务。CCEP显示了屏状核间及屏状核与海马之间的连接性。一些KA癫痫发作似乎起源于屏状核。
操作条件反射任务的结果表明，屏状核刺激可改变注意力或意识。CCEP显示了双侧屏状核之间以及屏状核与海马之间的连接性。这种连接性可能是边缘系统癫痫发作时意识改变基础神经回路的一部分。最后，KA癫痫发作显示屏状核早期受累，这一发现也支持屏状核在认知障碍性癫痫发作伴随的意识改变中可能发挥的作用。
