超声刺激对大鼠多皮层ECoG的调控

目的:为了进一步揭示超声刺激的神经调控机制以及超声刺激引起的刺激效应范围,将超声刺激经颅施加到大鼠前额叶皮层部位,同步记录和分析前额叶、顶叶及枕叶皮层的皮层电位（Electrocorticogram, ECoG）的变化特征。方法:在大鼠麻醉状态下,利用脑立体定位仪将超声探头定位在大鼠前额叶部位的正上方,刺激时间为20 min。以功率谱密度（Power Spectral Density, PSD）、振幅及互相关系数值为指标,分析比较超声刺激前、刺激中、刺激后的ECoG总功率、平均幅值以及皮层间的互相关系数值。结果:（1）超声刺激会增加前额叶皮层ECoG的总PSD和平均幅值（P<0.05）,超声刺激停止后,在较短的时间内ECoG恢复到刺激前水平;（2）在顶叶及枕叶皮层,超声刺激对总ECoG及各频段信号的PSD、平均幅值无显著性影响。但在超声刺激过程中,枕叶ECoG的部分时间段的平均幅值相对于刺激前有显著性差异,即在超声刺激的后半段时间内,超声刺激产生刺激效应范围扩散到枕叶皮层。结论:超声刺激对刺激局部的ECoG具有调控作用,且这种调控具有及时性及快速恢复的特点。超声刺激对ECoG的调控效应范围总体上来说是局限性的,对远离刺激部位的其他脑皮层ECoG的影响尚无明确关系,其效应很可能是超声刺激局部引起的后续神经网络反应。 【关键词】超声刺激;ECoG;脑皮层;神经调控     

Propagation of focal cortical epileptiform discharge to the entopeduncular nucleus: Effect of caudate lesions

Single-unit recordings were made in the entopeduncular nucleus of cats which had previously undergone ipsilateral caudate lesions. During penicillin-induced epileptiform discharge from the pericruciate cortex, the percentage of responsive entopeduncular neurons in animals with a lesion was less than 20%. In a previous study in intact cats and in control experiments in the present study the percentage of responsive entopeduncular cells was more than 75%. These results indicate that propagation of epileptic discharge through the basal ganglia depends on intact pathways from the cortex to the caudate and from the caudate to the entopeduncular nucleus.     

ECoG、EEG、fMRI及SEEG在MRI阴性癫痫患者外科手术中的应用

目的 探讨皮层脑电图（ECoG）、脑电图（EEG）、功能磁共振成像（fMRI）及立体定向脑电图（SEEG）在磁共振成像（MRI）阴性的癫痫患者外科手术的应用。方法 选取2016年1月—2019年12月在新疆医科大学第一附属医院经MRI检查为阴性的癫痫患者246例,均对其行EEG、fMRI以定位致病灶。对致病灶定位明确者行手术切除治疗,另术中根据情况再次行ECoG或SEEG检查,术后再行fMRI、EEG检查。结果 EEG检查致病灶明确率为79.27%（195/246）,fMRI检查致病灶明确率为79.67%（196/246）,两者致病灶明确率比较,差异无统计学意义（P＞0.05）;经EEG与fMRI检查均未见明显异常放电者有50例;ECoG与SEEG检查致病灶明确率分别为100.00%（26/26）和100.00%（24/24）,两者检查致病灶明确率比较,差异无统计学意义（P＞0.05）。结论 EEG、fMRI、SEEG、ECoG检查在MRI阴性癫痫患者的致痫灶定位及手术切除指导中具有较好的应用价值,可精确定位并有效指引手术治疗。     

癫痫发作时的脑电图研究

目的：探讨各类癫痫发作时ＥＥＧ的演变过程。提高癫痫分类的准确度。达到更好的治疗效果。方法：对２２例癫痫临床发作时的ＥＥＧ进行分析。结果：发作时ＥＥＧ阳性率１００％。结论：脑电图是在癫痫诊断中不可缺少的手段，比任何其它方法都优越，特别是发作时的脑电图为癫痫诊断的最基本要素。     

Arterial hypotension triggers perifocal depolarizations and aggravates secondary damage in focal brain injury

Perifocal depolarizations (PFD) have been observed after traumatic brain injury, are known to disturb cerebrovascular reactivity and thus may contribute to the morphological consequences of brain injury. In this investigation, the role of PFD was studied in focal brain lesions with/without induction of delayed hypotension. Cerebral freeze lesions were induced in anesthetized normotensive rats that underwent perfusion fixation of brains 5 min, 4 h or 24 h after lesioning, respectively, to obtain quantitative histopathology. In additional groups, a 45-min period of moderate hypobaric hypotension was applied 15 min post-trauma and brains were perfusion fixed after 4 h or 24 h. In a second series, the direct current (DC) potential and cortical laser-Doppler flow (LDF) were measured adjacent to lesions under normotensive or hypotensive conditions. Sham procedures were carried out in rats that underwent hypotension alone. Lesioning resulted in a significant LDF decrease to 50% of baseline, further decreased during hypotension to less than 40% of control (P < 0.05). Sham animals had LDF values between 60 and 70% of control when subjected to hypotension. Focal brain injury always induced a negative DC shift shortly after lesioning. In 6 of 8 rats that underwent cold lesion plus hypotension, a second PFD was observed approximately 2.5 min after onset of hypotension accompanied by a relative LDF increase by 25 +/- 12%. Lesion expansion was significantly worsened by hypotension (8.19 +/- 0.56 mm(3) at 24 h) compared with normotensive rats (7.01 +/- 0.3 mm(3) at 24 h, P < 0.01). We conclude that hypotension triggers depolarizations by an ischemic mechanism that contributes to final tissue damage.     

诱发电位联合皮层脑电监测指导中央区继发性癫痫手术治疗

【摘要】 目的 探讨联合皮层体感诱发电位(Co-SEP)、皮层运动诱发电位（Co-MEP）、及皮层脑电监测（ECoG）对进行大脑功能区和致痫灶定位并手术治疗的效果。方法 30例致痫灶位于中央区及其邻近部位的癫痫患者,术前通过神经影像、电生理等技术综合评估,术中运用Co-SEP、Co-MEP、ECoG,准确定位致痫灶及功能区,尽量全切病变及致痫灶治疗继发性癫痫,同时保护重要脑功能。结果 根据Engel标准,对30例病人术后随访6～18个月,Ⅰ级者18例;Ⅱ级者7例,Ⅲ级者3例,Ⅳ级者2例。所有病人术后均无永久性肢体运动功能障碍。结论 术中联合Co-SEP、Co-MEP、ECoG,能安全、准确、有效的指导脑中央区病变及致痫灶的治疗,在避免运动皮层损伤的同时,最大限度切除病变,治疗继发性癫痫,提高患者的生存质量。     

Engagement of cortico-cortical and cortico-subcortical networks in a patient with epileptic spasms: An integrated neurophysiological study

ObjectiveWe aimed to delineate the engagement of cortico-cortical and cortico-subcortical networks in the generation of epileptic spasms (ES) using integrated neurophysiological techniques.MethodsSeventeen-year-old male patient with intractable ES underwent chronic subdural electrode implantation for presurgical evaluation. Networks were evaluated in ictal periods using high-frequency oscillation (HFO) analysis and in interictal periods using magnetoencephalography (MEG) and simultaneous electroencephalography, and functional magnetic resonance imaging (EEG-fMRI). Cortico-cortical evoked potentials (CCEPs) were recorded to trace connections among the networks.ResultsIctal HFO revealed a network comprising multilobar cortical regions (frontal, parietal, and temporal), but sparing the positive motor area. Interictally, MEG and EEG-fMRI revealed spike-and-wave-related activation in these cortical regions. Analysis of CCEPs provided evidence of connectivity within the cortico-cortical network. Additionally, EEG-fMRI results indicate the involvement of subcortical structures, such as bilateral thalamus (predominantly right) and midbrain.ConclusionsIn this case study, integrated neurophysiological techniques provided converging evidence for the involvement of a cortico-cortical network (sparing the positive motor area) and a cortico-subcortical network in the generation of ES in the patient.SignificanceCortico-cortical and cortico-subcortical pathways, with the exception of the direct descending corticospinal pathway from the positive motor area, may play important roles in the generation of ES.     

Electrocorticography in temporal lobe epilepsy surgery

The results of intra-operative cortical EEG recordings (ECoG) were assessed in 30 patients with medically refractory complex partial seizures submitted to temporal lobectomy. Interictal spiking was most frequently recorded from mesial temporal lobe structures (amygdaloid-hippocampal region) and from the temporal neocortex synchronously, as observed in 21/30 patients. In 7 patients, the interictal spiking involved the temporal neocortex exclusively. Electrical stimulation of mesial temporal lobe structures reproduced the patient's habitual warning in 10 patients. The results of this study confirms that ECoG provides reliable intra-operative mapping of the epileptogenic brain tissue to be excised.