Immunologic-mediated eustachian tube obstruction: a double-blind crossover study

Eight subjects with seasonal allergic rhinitis confirmed by positive skin tests and serum radioallergosorbent test to ragweed or timothy grass pollen were identified. A double-blind provocative antigen challenge was performed with intranasal insufflation of 50 mg of dry pollen to which the subject was either sensitive (ragweed or timothy) or not sensitive (pine). Before and after pollen insufflation, measurements of nasal function by nasal rhinomanometry and eustachian tube (ET) function by the nine-step tympanometry test were performed for up to 14 days. The ability to dilate the ET was documented in 14 of the 16 ears of the eight subjects before challenge. Within 30 min after antigen challenge transient obstruction of the ET associated with inability to dilate upon swallowing was observed in all 14 ears. Clinical symptoms of allergic rhinitis, including rhinorrhea and nasal obstruction, were produced in all subjects. ET function changes were reversible in three of 14 ears within 2 hr but persisted for more than 3 days in six of the ears. As a control, insufflation of pine pollen did not alter ET function or rhinomanometric values or produce clinical symptoms in the eight subjects. These findings suggest an allergic basis for ET obstruction and possibly for the development of otitis media with effusion.     

The truth-telling motor cortex: response competition in M1 discloses deceptive behaviour

Neural circuits associated with response conflict are active during deception. Here we use transcranial magnetic stimulation to examine for the first time whether competing responses in primary motor cortex can be used to detect lies. Participants used their little finger or thumb to respond either truthfully or deceitfully regarding facial familiarity. Motor-evoked-potentials (MEPs) from muscles associated with both digits tracked the development of each motor plan. When preparing to deceive, the MEP of the non-responding digit (i.e. the plan corresponding to the truth) exceeds the MEP of the responding digit (i.e. the lie), whereas a mirror-reversed pattern occurs when telling the truth. This give away response conflict interacts with the time of stimulation during a speeded reaction period. Lies can even activate digit-specific cortical representations when only verbal responses are made. Our findings support neurobiological models which blend cognitive decision-making with motor programming, and suggest a novel index for discriminating between honest and intentionally false facial recognition.     

帕金森病模型大鼠经颅磁刺激运动诱发电位皮层阈值的研究

目的:通过对帕金森病(Parkinson disease,PD)模型大鼠经颅磁刺激(transcranial magnetic stimulation,TMS)运动诱发电位(MEP)皮层阈值(cortical threshold,Ct)的研究,以明确PD的Ct测值以及随病情发展的变化情况,以期为PD临床提供电生理学实验研究依据.方法:实验动物为健康的Sprague-Dawley(SD)雄性大鼠40只,随机分为两组:①实验组(PD模型组)28只;②对照组(生理盐水组)12只.选取其右侧中脑黑质致密部(substantia nigra pars compacta,SNc)与腹侧被盖(ventra tegmental area,VTA)作为靶点,实验组注射6-羟基多巴胺(6-OHDA)以制备PD动物模型,对照组注射同等体积的生理盐水用于比较,于制模前、制模后1周、3周分别行双下肢记录的Ct检查.结果统计采用SPSS 11.5统计软件处理,P＜0.05为差异有显著意义.结果:术后1周,实验组在右侧中脑靶点TMS时于左下肢记录到的Ct较对照组降低,具有统计学意义(P＜0.05),实验组自身左右侧TMS-MEP比较,左下肢Ct较右下肢降低(P＜0.05);制模前、术后1周、术后3周实验组大鼠左下肢Ct进行性降低(P＜0.01);实验组大鼠右下肢及对照组大鼠左侧及右侧下肢Ct比较差异无显著意义(P＞0.05).结论:PD模型大鼠损毁侧Ct增加,PD模型大鼠病情越重、病程越长,Ct增加越明显.     

Biophysical modeling of neural plasticity induced by transcranial magnetic stimulation

Transcranial magnetic stimulation (TMS) is a widely used noninvasive brain stimulation method capable of inducing plastic reorganisation of cortical circuits in humans. Changes in neural activity following TMS are often attributed to synaptic plasticity via process of long-term potentiation and depression (LTP/LTD). However, the precise way in which synaptic processes such as LTP/LTD modulate the activity of large populations of neurons, as stimulated en masse by TMS, are unclear. The recent development of biophysical models, which incorporate the physiological properties of TMS-induced plasticity mathematically, provide an excellent framework for reconciling synaptic and macroscopic plasticity. This article overviews the TMS paradigms used to induce plasticity, and their limitations. It then describes the development of biophysically-based numerical models of the mechanisms underlying LTP/LTD on population-level neuronal activity, and the application of these models to TMS plasticity paradigms, including theta burst and paired associative stimulation. Finally, it outlines how modeling can complement experimental work to improve mechanistic understandings and optimize outcomes of TMS-induced plasticity.     

Task-dependent activation of distinct fast and slow(er) motor pathways during motor imagery

Background

Motor imagery and actual movements share overlapping activation of brain areas but little is known about task-specific activation of distinct motor pathways during mental simulation of movements. For real contractions, it was demonstrated that the slow(er) motor pathways are activated differently in ballistic compared to tonic contractions but it is unknown if this also holds true for imagined contractions.

tDCS changes in motor excitability are specific to orientation of current flow

Background

Measurements and models of current flow in the brain during transcranial Direct Current Stimulation (tDCS) indicate stimulation of regions in-between electrodes. Moreover, the folded cortex results in local fluctuations in current flow intensity and direction, and animal studies suggest current flow direction relative to cortical columns determines response to tDCS.

Surgical treatment and prognosis of adult patients with brainstem gliomas

The paper presents 47 adult patients who were surgically treated due to brainstem gliomas. Thirteen patients presented with contrast-enhancing Grades III and IV gliomas, according to the WHO classification, 13 patients with contrast-enhancing tumours originating from the glial cells (Grade I; WHO classification), 9 patients with diffuse gliomas, 5 patients with tectal brainstem gliomas and 7 patients with exophytic brainstem gliomas. During the surgical procedure, neuronavigation and the diffusion tensor tractography (DTI) of the corticospinal tract were used with the examination of motor evoked potentials (MEPs) and somatosensory evoked potentials (SSEPs) with direct stimulation of the fundus of the fourth brain ventricle in order to define the localization of the nuclei of nerves VII, IX, X and XII. Cerebellar dysfunction, damage to cranial nerves and dysphagia were the most frequent postoperative sequelae which were also the most difficult to resolve. The Karnofsky score established preoperatively and the extent of tumour resection were the factors affecting the prognosis. The mean time of progression-free survival (14 months) and the mean survival time after surgery (20 months) were the shortest for malignant brainstem gliomas. In the group with tectal brainstem gliomas, no cases of progression were found and none of the patients died during the follow-up. Some patients were professionally active. Partial resection of diffuse brainstem gliomas did not prolong the mean survival above 5 years. However, some patients survived over 5 years in good condition.     

SEP联合MEP监测在颅内动脉瘤夹闭术中的应用研究

目的 分析在接受颅内动脉瘤夹闭术患者中使用体感诱发电位和经颅电刺激运动诱发电位联合监测进行手术监测的效果。方法 回顾分析2014年12月~2015年12月我院收治的90例接受颅内动脉瘤夹闭术的患者作为研究对象,将其分对照组与观察组,各45例,对照组患者不采用电生理监测,观察组患者使用SEP与MEP联合监测,对比两组患者的术后效果及相应指标。结果 术后,观察组患者重度瘫痪率、术后并发症率、再手术率以及住院天数均低于或少于对照组,差异有统计学意义（P＜0.05）。结论 颅内动脉瘤夹闭术患者使用SEP与MEP联合监测对于提高术中指导水平及术后恢复质量均具有积极意义,同时可降低术后缺血性脑卒中发生率,应用价值较高。     

Resting-state EEG gamma power and theta–gamma coupling enhancement following high-frequency left dorsolateral prefrontal rTMS in patients with depression

Objective

We aimed to investigate neuromodulatory effects of high-frequency left dorsolateral prefrontal cortex repetitive transcranial magnetic stimulation (rTMS) on resting-state electroencephalography (EEG) and their clinical and cognitive correlates in patients with depression.