Reciprocal functional connections of the olfactory bulbs and other olfactory related areas with the prefrontal cortex

Reciprocal putative connections of the prefrontal cortex (PFC) (agranular insular, ventral and lateral orbital region) with the ipsi and contralateral main olfactory bulb (IOB; COB), the mediodorsal thalamic nucleus (MD), the basolateral amygdaloid nucleus (BLA) and the piriform cortex (PC) were investigated with electrophysiological techniques. Evoked field responses and orthodromic unit driving, generated in PFC following electrical stimulation of the above mentioned structures, were abolished following topical application of KCl, except for COB evoked mass potentials. Thus, locally generated activity was elicited in agranular insular cortex following IOB activation, the same region where recently, the taste cortex in the rat was localized. Since gustatory-visceral afferent information reaches insular cortex via 2-3 synaptic relays, autonomic, olfactory and gustatory inputs may interact at this level, and, as suggested previously for the mouse, play a key integrative role in flavor perception. Antidromically invaded neurons, 47% of which were identified by the collision-extinction technique, were also found in PFC areas which overlapped to a considerable extent with those from which orthodromic unit responses were obtained. In particular, closely spaced neurons in ventrolateral orbital (VLO) and lateral orbital (LO) regions were antidromically invaded following IOB and PC shocks; some neurons antidromically discharged by IOB were also transsynaptically activated following PC stimulation. These findings are in agreement with recent neuroanatomical studies which demonstrate axonal projections from PFC neurons to the IOB and COB in the rat and South American armadillo. In addition, stimulation of PFC regions dorsal to the rhinal fissure mostly inhibited spontaneous unit discharges recorded at the mitral cell layer of the IOB, suggesting that this effect may be partially mediated by excitatory inputs of prefrontal axons onto granule cells. The conduction properties, antidromic thresholds and activity-dependent variations in conduction velocity (CV) of bulbopetal neurons in prefrontal cortex were found to be similar to those exhibited by cells projecting to the IOB from olfactory peduncle regions, but not to those present in bulbopetal neurons of the horizontal limb of diagonal band, indicating that the OB may be subjected to centrifugal control by at least two cell groups differing in both histochemical and electrophysiological properties.     

Group II metabotropic glutamate receptors in the striatum of non-human primates: dysregulation following chronic cocaine self-administration

The purpose of this study was to investigate the possible effects of a treadmill training program on regeneration in young (3-month-old) and mature (13-month-old) rats with sciatic nerve crush using functional, electrophysiological, and morphometric analyses. When compared to both the young and mature untrained injury groups, those groups that underwent a treadmill training showed improved sensorimotor function evaluated by narrow beam test (p < 0.04 and p < 0.001, respectively), while muscle action potential amplitude was only greater in the young group (p < 0.02). The treadmill training program was able to reduce myelinated fiber density in the young group (p < 0.001), which appeared to increase after nerve injury (poly-innervation), but decreased with training, which means that the innervation became more functional. The data indicate that treadmill training is able to promote functional, electrophysiological and morphological recovery in young animals. However, in mature animals, improvement was only seen in terms of functional recovery.     

小鼠神经缺损管式修复后长时程功能恢复与再生评价

目的了解壳聚糖/聚乳酸-乙醇酸共聚体(PLGA)人工神经移植物修复小鼠神经缺损后神经功能长时程恢复水平与再生神经成熟度。方法采用人工神经移植物桥接修复小鼠坐骨神经缺损(n=6),以自体神经修复(n=6)和缺损组(n=6)为对照,术后1年采用热痛阈测定、电生理学、激光多普勒血流检测评定神经功能,采用靶肌湿重比、组织学和电子显微镜等技术综合评定神经重支配和再生神经成熟度。结果人工神经移植物组足底痛觉反应潜伏期、神经源性血管扩张程度、腓肠肌复合肌动作电位(CMAPs)波幅和潜伏期、靶肌湿重比、再生轴突数量等指标与自体神经修复组相近,但与健侧相比CMAPs潜伏期较长,髓鞘较薄,轴突直径分布滞后。结论人工神经移植物修复小鼠神经缺损术后1年感觉及自主神经功能、再生神经数量和靶肌重支配水平与自体神经修复相当,但再生神经纤维成熟度未达正常。     

Electrophysiological properties of neurons in the robust nucleus of the arcopallium of adult male zebra finches

Nucleus robust arcopallium (RA) of the songbird is a distinct forebrain region that is essential for song production. To explore the electrophysiological properties, whole cell recordings were made from adult zebra finch RA neurons in slice preparations. Based on the electrophysiological properties, neurons in RA were classified into two distinct classes. Type I neurons were spontaneously active. They had larger input resistance, longer time constant, larger time-peak of an afterhyperpolarization (AHP), and broader action potentials than those of the other class. A slow, time-dependent inward rectification was induced by hyperpolarizing current pulses in this type of neuron, and was blocked by external CsCl (2mM). Type II neurons had a more negative resting membrane potential than that of type I neurons. They were characterized by a steeper slope of the recovery from the peak of the AHP and frequency-current relationships, a higher firing threshold, and irregular spiking in response to depolarizing current injection.     

Stability of Late Event-Related Potentials: Topographical Descriptors of Motor Control Compared with the P300 Amplitude

The P300-amplitude evoked with an acoustic oddball-paradigm is considered the most stable late event-related potential (ERP). This amplitude-index has become a standard parameter in electrophysiology. Recently, a robust ERP-parameter (NoGo-anteriorization, NGA) has been introduced, which reflects spatial brain electrical changes in relation to execution and inhibition of a motor response elicited with a Continuous Performance Test (CPT). The current study refers to the stability of this new topographical ERP-parameter compared to the stability of the classical P300-amplitude. For that purpose, 12 healthy subjects were investigated with both paradigms during recording of a 21-channel EEG. Analysis of the resulting ERPs revealed a very high stability for both, topographical and amplitude index: In every single subject, the brain electrical fields were characterized by a more anterior location in the NoGo- compared to the Go-condition (=NGA) and by higher amplitudes after target compared to distractor condition. T-tests, analyses of the effect size and of the power revealed equivalent differences between the two contrasting conditions for the topographical compared to the amplitude index. These results indicate that the stability of the topographical ERP-parameters elicited with the CPT is sufficient for an electrophysiological standard-index. The possibility to elicit a robust and specific spatial brain activation with the CPT is an ideal completion to the classical P300 amplitude effect and, therefore, hopefully will be a useful expansion of the standard paradigms in electrophysiological laboratories.     

老年Miller-Fisher综合征患者的临床和神经电生理特点分析

目的研究老年Miller-Fisher综合征(MFS)患者的临床和电生理特征,并分析其预后。方法对9例老年MFS患者的临床表现、辅助检查、治疗和预后进行回顾性总结分析。结果本组男女比例4:5,患病年龄(68.3±4.1)岁,病程(19.2±9.9)d,发病主要在春冬季节,有呼吸道感染前驱史者3例,首发症状主要为头晕、头痛、眼睑下垂、复视、行走不稳和肢体麻木无力,起病至达峰平均(2.7±2.8)d;患者均有眼肌麻痹、共济失调和腱反射减弱或消失,眼胀痛5例,眼内肌受累2例,面神经受累4例,舌咽、迷走神经受累3例,四肢肌力减退3例,远端浅感觉减退或消失6例,自主神经受累3例;血清抗GQ1b抗体阳性5例,脑脊液示蛋白细胞分离6例,四肢肌电图异常7例,主要表现为感觉神经传导受累5例;患者应用激素和(或)免疫球蛋白治疗,头痛、眼胀痛、肢体麻木症状最早改善,眼外肌麻痹、共济失调分别在(2.5±1.5)d、(6.3±3.8)d时开始改善,腱反射异常在2~3周出院时无明显恢复;患者住院(15.0±4.6)d,出院时均好转。结论老年MFS临床表现多样,肌电图主要表现为感觉神经传导受累,血清抗GQ1b抗体有助于诊断,激素和(或)免疫球蛋白治疗后好转。     

Effects of bacterial melanin on motor recovery and regeneration after unilateral destruction of Substantia Nigra pars compacta in rats

We examined the potential neuroprotective action of bacterial melanin (BM) in rats after unilateral destruction of Substantia Nigra pars compacta (SNc) dopaminergic neurons. 24 rats were initially trained to an instrumental conditioned reflex (ICR) and then subjected to unilateral electrolytic destruction of SNc. Unilateral deficit in balancing hindlimb movements was observed in all rats after the destruction. On the next day after the destruction part of the animals (n = 12) was intramuscularly injected with BM solution at the concentration 6 mg/ml (0.17 g/kg). The other 12 operated rats served as a control group. On the second day after the operation the testing of instrumental conditioned reflex was resumed in both groups.     

颈椎前路植骨融合内固定术治疗平山病疗效的电生理评估

【摘要】 目的：通过电生理技术对接受颈椎前路植骨融合内固定手术治疗的平山病患者手术前后神经功能进行评估,探究手术干预对于神经功能恢复的作用。方法：回顾性分析2016年1月~2017年7月于我院骨科接受颈椎前路植骨融合内固定手术的平山病患者43例,其中男性41例,女性2例;手术时年龄14~26岁,平均18.2±2.8岁,病程6~84个月,平均22.3±20.1个月;随访时间3~18个月,平均7.2±4.4个月。所有患者均在术前及末次随访时接受上肢神经传导检查、针肌电图检查和上肢功能障碍评定（disability of arm shoulder hand,DASH）量表评估。通过比较复合肌肉动作电位（compound muscle action potential,CMAP）波幅、肌肉自发电位、运动单位电位形态及肌肉募集情况评估患者术后神经功能改变,并通过DASH量表评分变化评估患者术后上肢功能变化。分别比较术前症状严重侧和轻侧及手术前后电生理检查结果,通过配对样本t检验比较CMAP波幅,Pearson卡方检验比较肌肉自发电位、运动单位电位形态及肌肉募集情况;通过配对样本t检验比较手术前后DASH量表评分变化。结果：患者手术前神经电生理检查结果显示,症状严重侧正中神经及尺神经波幅较轻侧明显降低（P＜0.05）,超过半数患者针肌电图检查可见双侧神经源性损害。术前及术后随访结果对比显示,术前症状严重侧正中神经CMAP波幅平均为9.79±4.63mV,术后平均为11.04±4.43mV,差异有统计学意义（P＜0.05）;术前症状严重侧尺神经CMAP波幅平均为4.04±3.25mV,术后平均为6.19±4.30mV,差异有统计学意义（P<0.001）。轻侧正中神经及尺神经CMAP波幅恢复情况无统计学意义（P＞0.05）;针肌电图检查结果显示,患者严重侧上肢被检肌肉自发电位出现比例、MUAP形态宽大比例下降无统计学意义（P>0.05）;部分被检肌肉募集情况有较为显著改善,其中术前42例患者症状严重侧桡侧腕屈肌存在募集减弱（42/43,97.7%）,末次随访时32例患者同一肌肉存在募集减弱（32/38,84.2%）,差异有统计学意义（P＜0.05）。患者术前DASH量表评分为7.04±7.63分,末次随访时6.89±7.47分,差异无统计学意义（P>0.05）。结论：平山病患者接受颈椎前路植骨融合内固定手术后,上肢CMAP波幅提高,肌肉募集情况改善,该手术对控制病情进展、改善神经功能有积极作用。     

Recurrent familial neuropathy with liability to pressure palsies

Summary Electrophysiological, histological and ultrastructural studies on two patients (one family) with familial neuropathy and a liability to pressure palsies are reported. There was slowing of nerve conduction velocities and increase of distal latencies of clinically affected and clinically non-affected nerves. These alterations were confirmed by biopsy of the sural nerve which had the characterized signs of the disease. Pathogenetically there seems to be an endogeneous metabolic defect of the Schwann cell to synthetize a normal myelin sheath, which is responsible for the particular susceptibility to mechanical damage.

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Zusammenfassung Es werden zwei Fälle einer familären rezidivierenden polytopen Neuropathie dargestellt. Es wird das klinische und elektrophysiologische Bild und die Charakteristika der lichtmikroskopischen und elektronenmikroskopischen Nervenveränderungen beschrieben. Elektrophysiologisch konnte nachgewiesen werden, daß die Verlangsamung der Nervenleitgeschwindigkeit und der distalen Latenzzeit auch klinisch nicht lädierte Nerven betrifft. Die typischen histologischen Merkmale dieser Krankheit waren in der Biopsie des N. suralis erkennbar. In pathogenetischer Hinsicht muß man wohl annehmen, daß es sich um eine endogene metabolische Entgleisung der Schwannschen Zelle handelt, die nicht mehr fähig ist, eine normale Myelin zu produzieren, die dann den mechanischen Noxen gegenüber besonders empfindlich wird.

     

A Low-Cost Precision Electrode Impedance Meter

A circuit is described which measures applied electrode impedances using a 7 P.A RMS, 10 Hz sine wave current, and displays the reading in ohms on a small analog meter. The design uses a minimum of parts and power, drawing only 2mA from a 9 volt battery, yet is accurate lo within 2% and can easily be modified to fit a wide range of frequencies.