皮层电极埋藏对累及运动功能区病灶切除的意义

目的 探讨手术治疗毗邻和侵犯中央区的病灶周边运动功能区的保护方法.方法 回顾分析6例病灶累及中央区的病例资料(5例为药物难治性癫痫,1例为颅内转移瘤),采用神经导航定位病灶,第一次手术埋藏皮层电极覆盖病灶,术外患者清醒状态下实施皮层电刺激定位躯体运动区,绘制病灶与功能区关系图,第二次手术依据皮层电刺激结果行病灶切除.结果 6例患者第一次术后,均成功实施皮层电刺激,准确定位病灶周边运动功能区.依据关系图第二次手术3例患者(2例药物难治性癫痫,l例颅内转移瘤)行病灶全切,3例患者(3例药物难治性癫痫)行部分病灶切除.术后无一例出现神经功能缺损.结论 神经导航定位病灶指导埋藏皮层电极,术外行皮层电刺激定位病灶周边运动功能区,绘制功能区与病灶关系图指导第二次手术切除病灶,是在保护患者运动功能前提下,最大范围切除累及中央区病灶的一种安全有效的方法.     

MEP latency shift after implantation of deep brain stimulation systems in the subthalamic nucleus in patients with advanced Parkinson's disease.

Deep brain stimulation (DBS) into the subthalamic nucleus (STN) is a highly effective treatment for advanced Parkinson's disease (PD). The consequences of STN stimulation on intracortical and corticospinal excitability have been addressed in a few studies using transcranial magnetic stimulation (TMS). Although excitability measurements were compared between the STN stimulation OFF and ON condition, in these experiments, there are no longitudinal studies examining the impact of electrode implantation per se on motor excitability. Here, we explored the effects of STN electrode implantation on resting motor thresholds (RMT), motor evoked potential (MEP) recruitment curves, and MEP onset latencies on 2 consecutive days before and shortly after STN surgery with the stimulator switched off, thus avoiding the effects of chronic DBS on the motor system, in 8 PD patients not taking any dopaminergic medication. After surgery, RMT and MEP recruitment curves were unchanged. In contrast, MEP onset latencies were significantly shorter when examined in relaxed muscles but were unchanged under preactivation. We hypothesize that postoperatively TMS pulses induced small currents in scalp leads underneath the TMS coil connecting the external stimulator with STN electrodes leading to inadvertent stimulation of fast-conducting descending neural elements in the vicinity of the STN, thereby producing submotor threshold descending volleys. These "conditioning" volleys probably preactivated spinal motor neurons leading to earlier suprathreshold activation by the multiple corticospinal volleys produced by TMS of the motor cortex. These TMS effects need to be considered when interpreting results of excitability measurements in PD patients after implantation of STN electrodes.     

显微手术夹闭治疗老年颅内动脉瘤的疗效(附49例报道)

目的 探讨显微手术夹闭治疗老年患者颅内动脉瘤的治疗效果.方法 回顾性分析49例60岁以上颅内动脉瘤患者的临床资料(包括破裂出血41例,未破裂出血8例).根据术前数字减影血管造影(DSA)和头颅CT血管造影(CTA)检查确认动脉瘤后,48例采用经翼点入路,1例采用经纵裂入路夹闭颅内动脉瘤,出院时根据格拉斯哥预后评分(GOS)评价预后.结果 根据GOS评分,41例破裂出血患者,Hunt-Hess分级Ⅰ~Ⅲ级28例,其中26例(93%)取得良好预后,重度残疾2例(7%);Hunt-Hess分级Ⅳ级13例,其中7例(54%)取得了良好的预后,重度残疾3例(23%),植物生存1例(8%),死亡2例(15%).未破裂动脉瘤8例,均取得良好预后(100%).结论 破裂动脉瘤的老年患者应尽可能早期手术,术前Hunt-Hess分级Ⅰ~Ⅲ级者预后良好,而Ⅳ级以上病死率和伤残率仍较高;未破裂动脉瘤老年患者应采取积极治疗.     

Deep brain stimulation of the posterior hypothalamus activates the histaminergic system to exert antiepileptic effect in rat pentylenetetrazol model

Deep brain stimulation (DBS) is a promising therapy for intractable epilepsy, yet the optimum target and underlying mechanism remain controversial. We used the rat pentylenetetrazol (PTZ) seizure model to evaluate the effectiveness of DBS to three targets: two known to be critical for arousal, the histaminergic tuberomammillary nucleus (TMN) and the orexin/hypocretinergic perifornical area (PFN), and the anterior thalamic nuclei (ATH) now in clinical trial. TMN stimulation provided the strong protection against the seizure, and PFN stimulation elicited a moderate effect yet accompanying abnormal behavior in 25% subjects, while ATH stimulation aggravated the seizure. Power density analysis showed EEG desynchronization after DBS on TMN and PFN, while DBS on ATH caused no effect with the same stimulation intensity. EEG desynchronization after TMN stimulation was inhibited in a dose-dependent manner by pyrilamine, a histamine H(1) receptor selective antagonist, while the effect of PFN stimulation was inhibited even at a low dose. In parallel, in vivo microdialysis revealed a prominent increase of histamine release in the frontal cortex after TMN stimulation, a moderate level with PFN and none with ATH. Furthermore, antiepileptic effect of DBS to TMN was also blocked by an H(1) receptor antagonist. This study clearly indicates that EEG desynchronization and the activation of the histaminergic system contributed to the antiepileptic effects caused by DBS to the posterior hypothalamus.     

The effect of dexmedetomidine on the firing properties of STN neurons in Parkinson's disease

Dexmedetomidine (an alpha‐2 adrenergic agonist) sedation is commonly used during subthalamic nucleus (STN) deep‐brain stimulation (DBS). Its effects on the electrophysiological characteristics of human STN neurons are largely unknown. We hypothesised that dexmedetomidine modulates the firing rates and bursting of human STN neurons. We analysed microelectrode recording (MER) data from patients with Parkinson's disease who underwent STN DBS. A ‘Dex bolus’ group (dexmedetomidine bolus prior to MER; 27 cells from seven patients) was compared with a ‘no sedation’ group (29 cells from 11 patients). We also performed within‐patient comparisons with varying dexmedetomidine states. Cells were classified as dorsal half or ventral half based on their relative location in the STN. Neuronal burst and oscillation characteristics were analysed using the Kaneoke–Vitek methodology and local field potential (LFP) oscillatory activity was also investigated. Dexmedetomidine was associated with a slight increase in firing rate (41.1 ± 9.9 vs. 34.5 ± 10.6 Hz, P = 0.02) but a significant decrease in burstiness (number of bursts, P = 0.02; burst index, P < 0.001; percentage of spikes in burst, P = 0.002) of dorsal but not ventral STN neurons. This was not associated with modulation of beta oscillations in the spike‐oscillations analysis(beta peak, P = 0.4; signal‐to‐noise ratio in the beta range for spikes and bursts, P = 0.3 and P = 0.5, respectively) and LFP analysis (Beta power, P = 0.17). As bursting pattern is often used to identify STN and guide electrode placement, we recommend that high‐dose dexmedetomidine should be avoided during DBS surgery.     

Functional outcome and quality of life in Tourette's syndrome after deep brain stimulation of the posteroventrolateral globus pallidus internus: long-term follow-up

Objectives. Deep brain stimulation (DBS) for Tourette's syndrome (TS) in various targets has been in the focus for some years. However, there are hardly any data on “psychosocial” outcome after DBS for TS. The aim of the present study therefore was to focus on the functional outcome and “psychosocial changes” in TS patients after DBS. Methods. Six patients with treatment-refractory TS underwent GPi-DBS. The Yale Global Tic Severity Scale (YGTSS) was used to evaluate symptomatic outcome. Psychosocial changes were assessed applying the Global Assessment of Functioning Scale (GAF) and the Gilles-de-la-Tourette-Syndrome Quality-of-Life scale (GTS-QOL) with additionally documenting psychosocial changes. Follow-up ranged between 12 and 72 months. Results. In all symptomatic responders (4 of 6) we found a significant functional improvement (mean GAF increasing from 53.75 (± 7.5) pre-operatively to 83.75 (± 7.5) at last follow-up) along with a positive correlation with the course of GTS-QOL (R² = 0.62). Conclusions. Treatment success should not only be assessed with the classic “tic-scales”, but also with the GAF and GTS-QOL. Although improvement of tics seems to be positively correlated with improved functional outcome, symptomatic improvement may lead to unexpected major psychosocial changes – which both the patient and the clinicians in charge – should be prepared for.     

深部电刺激伏隔核对吗啡成瘾大鼠复吸后伏隔核内γ-氨基丁酸含量变化的影响

目的研究深部电刺激(deep brain stimulation,DBS)双侧伏隔核对吗啡成瘾大鼠复吸后伏隔核内γ-氨基丁酸(γ-aminobutyric Acid,GABA)含量的影响。方法手术前使用条件性位置偏爱试验(conditionedplace preference,CPP)筛选无自然偏爱大鼠,随机分组后DBS组行电极植入术,术后10天采用固定剂量吗啡皮下注射(10mg.Kg-1)建立吗啡成瘾大鼠模型(使用CPP证实)。通过改进的DBS电路进行电刺激(频率130Hz,电流300uA,电压1V,1h.d-1),在不同的时间点使用CPP证实DBS组大鼠戒断成功后再皮下给予小剂量吗啡(3mg.Kg-1),24h后使用CPP验证吗啡成瘾大鼠复吸模型建立成功。CPP试验结束后于冰台上按大鼠脑立体定位图谱取伏隔核行高效液相色谱法(high performance liquid chromatography,HPLC)测定GABA含量。结果①皮下注射固定剂量吗啡能够使大鼠成瘾,DBS能够有效抑制吗啡复吸行为;②morphine+DBS组大鼠伏隔核内GABA含量与吗啡组,morphine+sham组差异明显。结论 DBS双侧伏隔核使吗啡成瘾大鼠复吸后伏隔核内GABA含量增加。     

The associative brain at work: Evidence from paired associative stimulation studies in humans

The original protocol of Paired Associative Stimulation (PAS) in humans implies repetitive cortical and peripheral nerve stimuli, delivered at specific inter-stimulus intervals, able to elicit non-invasively long-term potentiation (LTP)- and long-term depression (LTD)-like plasticity in the human motor cortex. PAS has been designed to drive cortical LTP/LTD according to the Hebbian rule of associative plasticity. Over the last two decades, a growing number of researchers have increasingly used the PAS technique to assess cortical associative plasticity in healthy humans and in patients with movement disorders and other neuropsychiatric diseases. The present review covers the physiology, pharmacology, pathology and motor effects of PAS. Further sections of the review focus on new protocols of “modified PAS” and possible future application of PAS in neuromorphic circuits designed for brain-computer interface.     

Effect of Deep Brain Stimulation of the ventromedial prefrontal cortex on the noradrenergic system in rats

Background

Deep Brain Stimulation (DBS) of the subgenual cingulate cortex (SCC) is a promising therapeutic alternative to treat resistant major depressive disorder. In preclinical studies, DBS of the ventromedial prefrontal cortex (vmPFC, the rodent SCC correlate) provokes an antidepressant-like effect, along with changes in noradrenaline levels at the site of stimulation. Hence, DBS appears to activate the noradrenergic-locus coeruleus (LC) system.